Question of manual settings for VX2100 at DVinfo.net

Dan Melius · July 9th, 2004, 03:15 AM

Hi all,

I am a newbie with two VX2100's. I will be filming spot lit concerts this summer and the instructions for the VX2100 seem to cover in detail on all the editing functions that I could care less about. The section on exposure and using the zebra bars was hopelessly inadequate. Here's a few questions that I have that maybe someone could answer.

The manual white balance -- Does anyone use that feature of filming a piece of white cardboard under the light conditions? I've tried this feature with my Sony DSC F-707 digital camera under florescent lights and found it to be better at taking pictures in automatic white balance mode. I will not be using my VX2100's for taking still pictures but assume that it uses the same technology as my still camera.

Also, I have a question on adjusting the exposure settings with the exposure set to manual mode. Is it the purpose to eliminate all the zebra lines or as many as possible? The instruction book spent one page on telling me how to get the zebra lines to come up but nothing on the proper use of them. I also have a training DVD that did not show anything on how to use them for best advantage.

I did read one comment on hear that stated to place the camera in automatic mode to see where the camera likes the zebra lines and then use that for an example in manual mode. If this is the case I might as well just use the automatic exposure with the spot light feature turned on as it does not seem to serve any purpose to duplicate the automatic mode just so I can say that I use manual exposure settings.

I am not one that is beyond using automatic settings if the camera can do a better job at getting it right than me.

Boyd Ostroff · July 9th, 2004, 05:48 AM

If you manually white balance be sure that it's to a clear stagelight at full intensity, not something with a gel or a light that has been dimmed down. And you will need to make some choices if it's a concert. By "spotlight" do you mean a follow spot (bright round circle of light on the performer)? These have xenon or HMI lamps typically which have a very high color temperature, approaching daylight. But then there may be a mix of other lights in use, like halogen PAR's and ellipsoidals that are much warmer. And some automated fixtures (like VariLites) may be lamped with HMI as well.

Your eye does a great job of adjusting to all this, but the camera doesn't. If you white balance for a xenon spot then all the halogen lamps will look yellow. Or if you balance for the halogen the spot will look blue. There really isn't an easy solution here, other than determining which is more important to you. If you will have mostly closeups of a single performer in a spotlight then you might try balancing to it (again, make sure there is no gel on the spotlight when you do this though). But if you want to film the whole stage, or areas of it light in halogen you are probably just as well off to use the built-in tungsten white balance.

The nice thing about the Sony cameras is that you can use the custom preset to shift white balance as desired to make it look the way you want. I think you're going to have to experiment a little in order to get things to look the way you like.

My experience is that the automatic modes aren't so good in this sort of situation, I never use them myself. But shooting a live show will involve constantly changing the iris setting in manual. Once you start shooting concerts I suspect you will also have some question about how to get good audio; the built-in mike will probably not do what you want, but give it a try.

Here are some other good threads covering the various facets of this topic that you might want to visit:

http://www.dvinfo.net/conf/showthrea...threadid=18431
http://www.dvinfo.net/conf/showthrea...threadid=21801
http://www.dvinfo.net/conf/showthrea...&threadid=5156
http://www.dvinfo.net/conf/showthrea...&threadid=8525

Dan Melius · July 9th, 2004, 06:53 AM

thanks for your input. The concets I will be filming at will be all over and I have no idea of what lights if any will be used at each place.

I already have one of my VX2100's modified by Greg Winter for sound and have a mixpre and Rode NT4 set up that I have been messing with for the last couple of weeks to see how it all works and the right settings for it. The singer's will also be proffesionally recording each of the concerts.

thanks

Dan Melius · July 9th, 2004, 06:58 AM

"By "spotlight" do you mean a follow spot (bright round circle of light on the performer)?"

I might have been talking about the spotlights that will more than less be used at least at some of the concerts and am not sure at all what kind they will be.

Or I may have been talking about using the automatic setting spotlight that is on the VX2100 that is suppose to take some of the white out of the faces.

Ray Echevers · July 9th, 2004, 08:25 AM

In case you haven't noticed, the VX-2100 has a "cold" picture, it likes to favor blue instead of red.
I use the custom presets all the time now and helps out a whole lot.
I have the white balance preset almost all the way to the right(more reds).
As far as zebras, i tried it for one day, but didn't really like it. In those situations with uneven lighting, it's still hard to tell where to set the exposure too. Maybe it's just me, but I find it a whole lot easier to set the manual exposure, manually.
Plus the viewfinder and lcd screen are really good on these cameras.
Sometimes if in the viewfinder i'm not 100% decided on what exposure I want, I flip out the Lcd screen and confirm or adjust more accordingly.

Mike Rehmus · July 9th, 2004, 10:53 AM

<<<-- Originally posted by Dan Melius : Hi all,
Also, I have a question on adjusting the exposure settings with the exposure set to manual mode. Is it the purpose to eliminate all the zebra lines or as many as possible? The instruction book spent one page on telling me how to get the zebra lines to come up but nothing on the proper use of them. I also have a training DVD that did not show anything on how to use them for best advantage.

-->>>

The best way to use the zebra for setting exposure is to insure that you are set up for 70% zebras. Get a caucasian test subject to stand in the typical white stage lighting and facing the auditorium. If you can zoom in to get a fairly large image of their face from your shooting position, good. Otherwise, move in closer. Adjust your exposure from too dark to the point where the zebra is just shown as a sort of fringe around the face. Don't come from the too bright direction.

Try several f-stops, recording each result. Check the results on a monitor and that will tell you exactly what you need to set. If you don't have an opportunity to go that far with testing or you feel confident, then set your aperature with the zebra just before the show goes on.

Then if they don't change stage lighting on you (happens all the time) you will be set up for proper face exposure. The rest of the stage will have to fall where it happens to fall.

If the talent are ethnically mixed, I may adjust the aperature by a half-stop but no more. I make a judgement call as I go.

A big help is the use of a field monitor to judge exposure. Sometimes I also use a waveform monitor if everything is really critical.

BTW, there are lots of posts on this subject in this and other forums. Please do a search.

Dan Melius · July 11th, 2004, 07:04 AM

Hi Mike,

thanks for the tips on setting the exposure. Do you use the manual white balance where you record a white piece of carboard in the same light source before you set the exposure? will have a good bit of time to set up the camera before the concert starts when they are doing their sound tests and tuning their insturments. Most places will set up the lighting at the same time.

For shutter speed I was thinking about keeping it at 1/60 manual setting for NTSC TV's and using the either of the ND filters only when the camera tells me that I need them after setting the white balance, exposure and shutter speed manually.

I have also received these comments by private emails as of late:

" i use 70% zebras when faces or colours are important and 100% when the scene is bright with a lot of whites or light colors."

" The Zebras have 2 settings. one for whites and one for skin tones and 18% greys.
At 100%, the zebras will show the limit to your whites. You adjust the aperture until the zebras only show on the very brightest part of the picture (whites). The 70% is for caucasian skin tones, grass, leaves, greys etc. the brightest skin tones should show the zebra crosshatch."

"Dan - I saw your response and wanted to let you know that I use 100% zebra bars and try to set my exposure so that I rarely get them - but for some subjects and bright flairs you can't get it perfect. Some zebra is OK. When the zebra bars are in the picture it just means that there is no more headroom to display white - it's known as 100% IRE. Not a biggie for projects going to DVD, it is a big deal if you plan to give stuff to a broadcast TV station that's all."

Dan Melius · July 11th, 2004, 07:10 AM

I guess the 70 percent manual exposure zebra setting would be most important to me for filming two caucasian singers playing accoustic instruments in spot lit concert halls.

They will be lighted with static lights that won't change throughout the concert and will be quite bright, which leads to the confusion of whether to use the 100 percent exposure zebra setting as that one is suppose to be for bright settings.

Here's some pictures of recent concerts they did sitting in chairs:

http://www.rockymountainministries.org/travel.html

Dan Melius · July 11th, 2004, 07:25 AM

Also, just to let you know I am red/Green color blind and will have to rely on the camera zebra settings or automatic settings in order to tell if the colors are right and let the camera do all of the work. It shouldn't be to big a deal judging from the above reading. Also I do have VX2100's but if I did have a PD 170, I would be limited to a black and white view finder anyway. It doesn't seem like color is that big a deal to proffesional camermen as they only have black and white on the real expensive cameras and in most cases don't have a color pop out LCD screen.

Mike Rehmus · July 11th, 2004, 12:31 PM

<<<-- Originally posted by Dan Melius : Hi Mike,

thanks for the tips on setting the exposure. Do you use the manual white balance where you record a white piece of carboard in the same light source before you set the exposure? will have a good bit of time to set up the camera before the concert starts when they are doing their sound tests and tuning their insturments. Most places will set up the lighting at the same time.

-------------------------
Yes, I white balance at the same time. Then I Lock the camera so nothing can be changed without a lot of thought.
-------------------------------------

For shutter speed I was thinking about keeping it at 1/60 manual setting for NTSC TV's and using the either of the ND filters only when the camera tells me that I need them after setting the white balance, exposure and shutter speed manually.

-----------------------
Sometimes I'll use 1/30th of a second if I have to.
---------------------

I have also received these comments by private emails as of late:

" i use 70% zebras when faces or colours are important and 100% when the scene is bright with a lot of whites or light colors."

------------------
Good
------------

" The Zebras have 2 settings. one for whites and one for skin tones and 18% greys.
At 100%, the zebras will show the limit to your whites. You adjust the aperture until the zebras only show on the very brightest part of the picture (whites). The 70% is for caucasian skin tones, grass, leaves, greys etc. the brightest skin tones should show the zebra crosshatch."

-------------------
You have to be very careful when using 100 IRE zebra. These cameras will pump out 110-120 IRE units at max white. That would make the video illegal for broadcast unless you tone it down in post. Best to do some tests.

BTW, the 18% gray card, which is quite expensive, can be printed with a laser or ink-jet printer. Or close enough which is what counts anyway.
--------------------

"Dan - I saw your response and wanted to let you know that I use 100% zebra bars and try to set my exposure so that I rarely get them - but for some subjects and bright flairs you can't get it perfect. Some zebra is OK. When the zebra bars are in the picture it just means that there is no more headroom to display white - it's known as 100% IRE. Not a biggie for projects going to DVD, it is a big deal if you plan to give stuff to a broadcast TV station that's all." -->>>

Dan Melius · July 12th, 2004, 05:39 AM

"BTW, the 18% gray card, which is quite expensive, can be printed with a laser or ink-jet printer. Or close enough which is what counts anyway."

Not sure I follow on the 18% gray card comment. Is this a special card paper that most people shoot into in order to white balance? I am not familar with what 18% gray term refers to. I was just going to use some white poster board.

Dan Melius · July 12th, 2004, 06:29 AM

Ok I was able to find the Kodak 18 percent gray cards from BH photo and ordered a pack as they were only 14 dollars.

What is the sequence for doing all this. Do you do it this way:

1. White balance with white card
2. 18 percent gray exposure card
3. 70 percent zebra setting on the person's face.

or does it not matter?

I did get a white balance card with my portabrace VX2100 bag. Does anyone know if you are suppose to use the shiny side or the dull side? I would assume the relective side would be best.

Mike Rehmus · July 12th, 2004, 12:16 PM

<<<-- Originally posted by Dan Melius : Ok I was able to find the Kodak 18 percent gray cards from BH photo and ordered a pack as they were only 14 dollars.

What is the sequence for doing all this. Do you do it this way:

1. White balance with white card
2. 18 percent gray exposure card
------------------------
Set the 70% zebra on this and you don't need to set up on the person's face.
------------------------

I did get a white balance card with my portabrace VX2100 bag. Does anyone know if you are suppose to use the shiny side or the dull side? I would assume the relective side would be best.

-------------------
Match the subject matter, I suppose. A shiny surface may reflect lamps and give you a hot spot.

Best way to white balance is with the camera defocused anyway. Then the surface finish won't matter as you won't get hot spots.
-------------------

-->>>

July 9th, 2004, 03:15 AM	#1
Dan Melius Regular Crew Join Date: May 2004 Location: Johnstown PA Posts: 44	Question of manual settings for VX2100 Hi all, I am a newbie with two VX2100's. I will be filming spot lit concerts this summer and the instructions for the VX2100 seem to cover in detail on all the editing functions that I could care less about. The section on exposure and using the zebra bars was hopelessly inadequate. Here's a few questions that I have that maybe someone could answer. The manual white balance -- Does anyone use that feature of filming a piece of white cardboard under the light conditions? I've tried this feature with my Sony DSC F-707 digital camera under florescent lights and found it to be better at taking pictures in automatic white balance mode. I will not be using my VX2100's for taking still pictures but assume that it uses the same technology as my still camera. Also, I have a question on adjusting the exposure settings with the exposure set to manual mode. Is it the purpose to eliminate all the zebra lines or as many as possible? The instruction book spent one page on telling me how to get the zebra lines to come up but nothing on the proper use of them. I also have a training DVD that did not show anything on how to use them for best advantage. I did read one comment on hear that stated to place the camera in automatic mode to see where the camera likes the zebra lines and then use that for an example in manual mode. If this is the case I might as well just use the automatic exposure with the spot light feature turned on as it does not seem to serve any purpose to duplicate the automatic mode just so I can say that I use manual exposure settings. I am not one that is beyond using automatic settings if the camera can do a better job at getting it right than me.

July 9th, 2004, 08:25 AM	#5
Ray Echevers Regular Crew Join Date: May 2004 Location: Somerville, MA Posts: 148	In case you haven't noticed, the VX-2100 has a "cold" picture, it likes to favor blue instead of red. I use the custom presets all the time now and helps out a whole lot. I have the white balance preset almost all the way to the right(more reds). As far as zebras, i tried it for one day, but didn't really like it. In those situations with uneven lighting, it's still hard to tell where to set the exposure too. Maybe it's just me, but I find it a whole lot easier to set the manual exposure, manually. Plus the viewfinder and lcd screen are really good on these cameras. Sometimes if in the viewfinder i'm not 100% decided on what exposure I want, I flip out the Lcd screen and confirm or adjust more accordingly. __________________ Sony VX-1000 G5 1.8 dual 91 Turbo MR2

July 9th, 2004, 10:53 AM	#6
Mike Rehmus Wrangler Join Date: May 2002 Location: Vallejo, California Posts: 4,049	Re: Question of manual settings for VX2100 <<<-- Originally posted by Dan Melius : Hi all, Also, I have a question on adjusting the exposure settings with the exposure set to manual mode. Is it the purpose to eliminate all the zebra lines or as many as possible? The instruction book spent one page on telling me how to get the zebra lines to come up but nothing on the proper use of them. I also have a training DVD that did not show anything on how to use them for best advantage. -->>> The best way to use the zebra for setting exposure is to insure that you are set up for 70% zebras. Get a caucasian test subject to stand in the typical white stage lighting and facing the auditorium. If you can zoom in to get a fairly large image of their face from your shooting position, good. Otherwise, move in closer. Adjust your exposure from too dark to the point where the zebra is just shown as a sort of fringe around the face. Don't come from the too bright direction. Try several f-stops, recording each result. Check the results on a monitor and that will tell you exactly what you need to set. If you don't have an opportunity to go that far with testing or you feel confident, then set your aperature with the zebra just before the show goes on. Then if they don't change stage lighting on you (happens all the time) you will be set up for proper face exposure. The rest of the stage will have to fall where it happens to fall. If the talent are ethnically mixed, I may adjust the aperature by a half-stop but no more. I make a judgement call as I go. A big help is the use of a field monitor to judge exposure. Sometimes I also use a waveform monitor if everything is really critical. BTW, there are lots of posts on this subject in this and other forums. Please do a search. __________________ Mike Rehmus Hey, I can see the carrot at the end of the tunnel!

July 11th, 2004, 12:31 PM	#10
Mike Rehmus Wrangler Join Date: May 2002 Location: Vallejo, California Posts: 4,049	<<<-- Originally posted by Dan Melius : Hi Mike, thanks for the tips on setting the exposure. Do you use the manual white balance where you record a white piece of carboard in the same light source before you set the exposure? will have a good bit of time to set up the camera before the concert starts when they are doing their sound tests and tuning their insturments. Most places will set up the lighting at the same time. ------------------------- Yes, I white balance at the same time. Then I Lock the camera so nothing can be changed without a lot of thought. ------------------------------------- For shutter speed I was thinking about keeping it at 1/60 manual setting for NTSC TV's and using the either of the ND filters only when the camera tells me that I need them after setting the white balance, exposure and shutter speed manually. ----------------------- Sometimes I'll use 1/30th of a second if I have to. --------------------- I have also received these comments by private emails as of late: " i use 70% zebras when faces or colours are important and 100% when the scene is bright with a lot of whites or light colors." ------------------ Good ------------ " The Zebras have 2 settings. one for whites and one for skin tones and 18% greys. At 100%, the zebras will show the limit to your whites. You adjust the aperture until the zebras only show on the very brightest part of the picture (whites). The 70% is for caucasian skin tones, grass, leaves, greys etc. the brightest skin tones should show the zebra crosshatch." ------------------- You have to be very careful when using 100 IRE zebra. These cameras will pump out 110-120 IRE units at max white. That would make the video illegal for broadcast unless you tone it down in post. Best to do some tests. BTW, the 18% gray card, which is quite expensive, can be printed with a laser or ink-jet printer. Or close enough which is what counts anyway. -------------------- "Dan - I saw your response and wanted to let you know that I use 100% zebra bars and try to set my exposure so that I rarely get them - but for some subjects and bright flairs you can't get it perfect. Some zebra is OK. When the zebra bars are in the picture it just means that there is no more headroom to display white - it's known as 100% IRE. Not a biggie for projects going to DVD, it is a big deal if you plan to give stuff to a broadcast TV station that's all." -->>> __________________ Mike Rehmus Hey, I can see the carrot at the end of the tunnel!

July 12th, 2004, 12:16 PM	#13
Mike Rehmus Wrangler Join Date: May 2002 Location: Vallejo, California Posts: 4,049	<<<-- Originally posted by Dan Melius : Ok I was able to find the Kodak 18 percent gray cards from BH photo and ordered a pack as they were only 14 dollars. What is the sequence for doing all this. Do you do it this way: 1. White balance with white card 2. 18 percent gray exposure card ------------------------ Set the 70% zebra on this and you don't need to set up on the person's face. ------------------------ I did get a white balance card with my portabrace VX2100 bag. Does anyone know if you are suppose to use the shiny side or the dull side? I would assume the relective side would be best. ------------------- Match the subject matter, I suppose. A shiny surface may reflect lamps and give you a hot spot. Best way to white balance is with the camera defocused anyway. Then the surface finish won't matter as you won't get hot spots. ------------------- -->>> __________________ Mike Rehmus Hey, I can see the carrot at the end of the tunnel!

July 9th, 2004, 05:48 AM	#2
Boyd Ostroff Wrangler Join Date: Dec 2002 Location: Mays Landing, NJ Posts: 11,802	If you manually white balance be sure that it's to a clear stagelight at full intensity, not something with a gel or a light that has been dimmed down. And you will need to make some choices if it's a concert. By "spotlight" do you mean a follow spot (bright round circle of light on the performer)? These have xenon or HMI lamps typically which have a very high color temperature, approaching daylight. But then there may be a mix of other lights in use, like halogen PAR's and ellipsoidals that are much warmer. And some automated fixtures (like VariLites) may be lamped with HMI as well. Your eye does a great job of adjusting to all this, but the camera doesn't. If you white balance for a xenon spot then all the halogen lamps will look yellow. Or if you balance for the halogen the spot will look blue. There really isn't an easy solution here, other than determining which is more important to you. If you will have mostly closeups of a single performer in a spotlight then you might try balancing to it (again, make sure there is no gel on the spotlight when you do this though). But if you want to film the whole stage, or areas of it light in halogen you are probably just as well off to use the built-in tungsten white balance. The nice thing about the Sony cameras is that you can use the custom preset to shift white balance as desired to make it look the way you want. I think you're going to have to experiment a little in order to get things to look the way you like. My experience is that the automatic modes aren't so good in this sort of situation, I never use them myself. But shooting a live show will involve constantly changing the iris setting in manual. Once you start shooting concerts I suspect you will also have some question about how to get good audio; the built-in mike will probably not do what you want, but give it a try. Here are some other good threads covering the various facets of this topic that you might want to visit: http://www.dvinfo.net/conf/showthrea...threadid=18431 http://www.dvinfo.net/conf/showthrea...threadid=21801 http://www.dvinfo.net/conf/showthrea...&threadid=5156 http://www.dvinfo.net/conf/showthrea...&threadid=8525

July 9th, 2004, 06:53 AM	#3
Dan Melius Regular Crew Join Date: May 2004 Location: Johnstown PA Posts: 44	thanks for your input. The concets I will be filming at will be all over and I have no idea of what lights if any will be used at each place. I already have one of my VX2100's modified by Greg Winter for sound and have a mixpre and Rode NT4 set up that I have been messing with for the last couple of weeks to see how it all works and the right settings for it. The singer's will also be proffesionally recording each of the concerts. thanks

July 9th, 2004, 06:58 AM	#4
Dan Melius Regular Crew Join Date: May 2004 Location: Johnstown PA Posts: 44	"By "spotlight" do you mean a follow spot (bright round circle of light on the performer)?" I might have been talking about the spotlights that will more than less be used at least at some of the concerts and am not sure at all what kind they will be. Or I may have been talking about using the automatic setting spotlight that is on the VX2100 that is suppose to take some of the white out of the faces.

July 11th, 2004, 07:04 AM	#7
Dan Melius Regular Crew Join Date: May 2004 Location: Johnstown PA Posts: 44	Hi Mike, thanks for the tips on setting the exposure. Do you use the manual white balance where you record a white piece of carboard in the same light source before you set the exposure? will have a good bit of time to set up the camera before the concert starts when they are doing their sound tests and tuning their insturments. Most places will set up the lighting at the same time. For shutter speed I was thinking about keeping it at 1/60 manual setting for NTSC TV's and using the either of the ND filters only when the camera tells me that I need them after setting the white balance, exposure and shutter speed manually. I have also received these comments by private emails as of late: " i use 70% zebras when faces or colours are important and 100% when the scene is bright with a lot of whites or light colors." " The Zebras have 2 settings. one for whites and one for skin tones and 18% greys. At 100%, the zebras will show the limit to your whites. You adjust the aperture until the zebras only show on the very brightest part of the picture (whites). The 70% is for caucasian skin tones, grass, leaves, greys etc. the brightest skin tones should show the zebra crosshatch." "Dan - I saw your response and wanted to let you know that I use 100% zebra bars and try to set my exposure so that I rarely get them - but for some subjects and bright flairs you can't get it perfect. Some zebra is OK. When the zebra bars are in the picture it just means that there is no more headroom to display white - it's known as 100% IRE. Not a biggie for projects going to DVD, it is a big deal if you plan to give stuff to a broadcast TV station that's all."

July 11th, 2004, 07:10 AM	#8
Dan Melius Regular Crew Join Date: May 2004 Location: Johnstown PA Posts: 44	I guess the 70 percent manual exposure zebra setting would be most important to me for filming two caucasian singers playing accoustic instruments in spot lit concert halls. They will be lighted with static lights that won't change throughout the concert and will be quite bright, which leads to the confusion of whether to use the 100 percent exposure zebra setting as that one is suppose to be for bright settings. Here's some pictures of recent concerts they did sitting in chairs: http://www.rockymountainministries.org/travel.html

July 11th, 2004, 07:25 AM	#9
Dan Melius Regular Crew Join Date: May 2004 Location: Johnstown PA Posts: 44	Also, just to let you know I am red/Green color blind and will have to rely on the camera zebra settings or automatic settings in order to tell if the colors are right and let the camera do all of the work. It shouldn't be to big a deal judging from the above reading. Also I do have VX2100's but if I did have a PD 170, I would be limited to a black and white view finder anyway. It doesn't seem like color is that big a deal to proffesional camermen as they only have black and white on the real expensive cameras and in most cases don't have a color pop out LCD screen.

July 12th, 2004, 05:39 AM	#11
Dan Melius Regular Crew Join Date: May 2004 Location: Johnstown PA Posts: 44	"BTW, the 18% gray card, which is quite expensive, can be printed with a laser or ink-jet printer. Or close enough which is what counts anyway." Not sure I follow on the 18% gray card comment. Is this a special card paper that most people shoot into in order to white balance? I am not familar with what 18% gray term refers to. I was just going to use some white poster board.

July 12th, 2004, 06:29 AM	#12
Dan Melius Regular Crew Join Date: May 2004 Location: Johnstown PA Posts: 44	Ok I was able to find the Kodak 18 percent gray cards from BH photo and ordered a pack as they were only 14 dollars. What is the sequence for doing all this. Do you do it this way: 1. White balance with white card 2. 18 percent gray exposure card 3. 70 percent zebra setting on the person's face. or does it not matter? I did get a white balance card with my portabrace VX2100 bag. Does anyone know if you are suppose to use the shiny side or the dull side? I would assume the relective side would be best.