White Balance and Warm Cards

[Darren Rousar]

Given the reported red problem with the A1, would WB with a non-white card help? I was looking at this system and thought it might cut down on some of the color correction possibly needed in post:

http://www.warmcards.com/

[Marc Ries]

Originally Posted by Darren Rousar

Given the reported red problem with the A1, would WB with a non-white card help? I was looking at this system and thought it might cut down on some of the color correction possibly needed in post:

http://www.warmcards.com/

I bought a the set for use with my HC1 and Nikon D70. Have not really had enough to time use them to really comment to much.

I bit pricey for the whole set, but you get what you pay for: a very nice holder, nice cards, a card laynard, etc. It's too bad though, they they could not offer just the one large warm card (the back is a white card), since that is what about 99% of the people would need.

[Nick Outram]

There is a sight on the web that has some bitmaps in the correct colours to print to make your own (sorry, link is on home PC and I am away for the week -try Google)

If you have a colour printer try printing some very light blue cards and white balancing on these...

You can easily make warm-up (blue), cool down (red) and neon correct (not sure)...


Nick.

[Darren Rousar]

Thanks for the responses guys.

I have Photoshop CS so I could do it myself. Don't know why I didn't think of that before :banghead:

So, does anyone have some tested and approved RGB settings worth trying?

[Peter Ferling]

I found a post in the warmcard forum, a poster there matched up the cards with PMS chips, and found the following:

Warm 1 = PMS 290 C
Warm 2 = PMS 2707 C
Warm 3 = PMS 283 C

I had my our layout expert look at the sample images (captures from timeline) comparing the HC1 with the XL1s. He mentioned that skin tones should be around (in cymk values) 20 cyan, 50 Magenta, and 60 Yellow (K is black and affects shades only).

I recorded myself wearing a black/grey small checkered polo, against a off-white wall with orange and blue signage attached. I was only using available light from a window on an overcast day.

He found it very interesting that the both the HC1 and Canon XL1s had similiar values in grey tones and whites. However, the skin tones were way off more so than other colors between the two. He noted that the yellow values of the HC1 were lacking. That is, in the HC1 they were even and in the XL1 it was consistently 8-10% more yellow. (which explains the red/pickish hue instead of the brown/tan hues the XL1 had rendered).

He's printing out a correct CYMK PSD of the above warm card settings (he has a calibrated system so the colors should be dead on). I'm going to redo the test and see what those results look like.

[Darren Rousar]

Originally Posted by Peter Ferling

I found a post in the warmcard forum,...

Good info, thanks.
Couldn't find the warmcard forum though.

[Peter Ferling]

Ok, I have some results, but I need a way to upload a dozen or so jpegs. What's a good free site so I can share?

[Darren Rousar]

Originally Posted by Peter Ferling

Ok, I have some results, but I need a way to upload a dozen or so jpegs. What's a good free site so I can share?

How big are the files? If not too large I might be able to host them for awhile.

[Peter Ferling]

I have them as tiffs, and I have to add a few titles and save to jpeg. Wife just put of plate a chops in front of me, a beer, and pointed to the grill. Guess she's trying to tell me something. I'll Get back to you in an hour. Thanks.

[Darren Rousar]

OK Peter, I'm at work (still :() until maybe 9pm. It's 5:30 in MSP now.

I suppose I should make sure they're not copyrighted. IE.- They're not simply scans from the WarmCards product?

[Peter Ferling]

I'm back, I'm stuffed. Office hours resume...

No scan's, logos or mentions of any particular brands -don't wanna go there.

Actually, DVinfo has an image gallery, maybe I should place them there and save you some bandwidth.

[Darren Rousar]

OK Peter,
Either way.
If the gallery doesn't work, let me know.

[Peter Ferling]

Subj: Warm balancing the Sony HDR-HC1.

Purpose:

To find a plausible solution in dealing with the Sony HDR-HC1 poor quality of reds and to improve (warm up) skin tones

Methodology:

Location:

I wanted to find an area that was diverse in color, warm and inviting, and well lit by natural sunlight. I chose an open waiting area in my work place, (my test is also pertinent to finding a suitable replacement for my aging XL1s so I’ve included that into the test as well).

Scene setup:

I did not include any additional lighting. I wanted to use as much available light as possible. The room also had a few overhead track lights, necessitating the need to create a custom white balance. (Many camera’s do a poor job in resolving a proper white balance in multiple lighting situations).

Other items included a hard back chair, a white board to block the harshest reflective sunlight (that was blowing out areas beyond 100 IRE), and an LCD monitor for focus.

Note: I also performed a similar test in the studio, under controlled lighting, but found the HC1 limited in dark situations, and it required some extra finesse in the lighting department, and is worthy of it’s own test (later). I believe this camera is more suited for daylight usage and that is why I chose an available light test. By not using lights I could keep the test simple, and not impose additional variables.

Unless full auto was used, the only additional settings for the HC1 was to decrease the sharpness to -1. Otherwise, everything was left at factory defaults. Zero gain and the highest exposure needed to achieve Zebra patterns at 100 IRE, and then backed off one setting. The canon wound up at F4, and the HC1 was 18 clicks left, or F1.8.

Both camera’s were shot within thirty minutes of each other, at mid-day when the sun’s temperature was even. I tested the XL1s first, since it’s the easier camera to setup and achieve the look I wanted, even if it was default settings.

I shot five clips with each camera, covering full auto, standard white balance, and three levels of warm balance using custom light blue swatches.

Light blue is used to shift the color gamut of the camera to a more red tone. This issue has been discussed before, and thanks goes to Greg Vaughn, for providing the PMS chip numbers that approximates the correct light blue hues used in this test. You can read the thread here:

http://www.dvinfo.net/conf/showthread.php?t=5434

Greg pointed out the following colors:
Warm 1 = PMS 290 C
Warm 2 = PMS 2707 C
Warm 3 = PMS 283 C

Since the actual PMS chips (used for print matching) are too small to balance against, I created some larger swatches based on the PMS colors within Photoshop, creating four small zones on an 8x11 sized image. I then asked our graphic artist to printout a color matched version of the sheet for use.

Granted, between Greg’s observations and the actual printout, you can guess that some offset has been encountered. However, the test called for using three shades of light blue, and so the exact blue needed is more of an art form and subject to personal taste. In this test, we are merely trying to see how much a difference this balancing act (had to say that) makes upon the final image.

After the shoot, the clips were captured into Premiere Pro 1.5.1 using standard DV for the XL1s, and a demo of Cineform’s Aspect HDV plugin v4 for the HC1.

Since the images were captured at or just below 100 IRE, I had to apply the Adobe ProcAmp filter, increasing the brightness and contrast, and also increase the White input (levels) to brighten the images for proper viewing on a PC monitor. They may appear a little washed out. However, I applied the exact same edits to all files.

I then exported a frame of roughly the same instance in each clip, labeled and compressed to jpeg for uploading. Again, keeping the compression settings the same for each.

Here's a link to my results:


http://www.dvinfo.net/gallery/browse...p?c=32&userid=



Discussion:

It would seem that the canon XL1s renders colors and skin tones more richly than the HC1. The HC1 has a more dominant pinkish hue present over the XL1, but my eyes tell me that the warm swatches are improving the image somewhat.

Our print guru informed me that correct skin tone should be around 20-30% Cyan, 50% Magenta and 60% Yellow.

The Canon images are generally closer to that truth, especially in the arms where the tones are more uniform. However, the HC1 is still showing some pink hues in Warm 3, though it's not so obvious when compared to full auto. The general effect seems more realistic (i.e. such a pink hue is expected).

However, you be the judge.

This was a fun experiment; I by no means am the expert. I simply took what I’ve learned about the subject and applied it in a one time, simple test. Please take it for what it is, and feel free to comment or suggest possible improvements. After all, were after the same goal (and I didn’t spend $1400 on toy and expect to put it on the shelf either : )

[Darren Rousar]

Thanks again Peter.
I took the PMS settings into Photoshop and made some cards.

Here's the web page for all to enjoy:

http://www.jmtype.com/WBCards.html

[Peter Ferling]

Your welcome. Nice job on the web site. I'm sure everyone will get a chance to try this out.