Microcrystalline Wax

[Frank Ladner]

Rai: Thanks! A high-def. with the ability to use 35mm lenses is the ultimate camera solution, I think. Especially if you can use variable framerates.

Obin: Thanks! I will try to post some 720x480 framegrabs from the first part of the movie when I get home. Oh, and I am using a Canon GL2.

[Rai Orz]

Obin, 720 verical lines is the border between visible and invisibly if you use a sill picture lens. I think your camera supply 1024 lines, but you would like to use only 720 so with the width of 1280Pixels you have a 16:9 format. If this is so, the picture on the GG is round 37,6 x 21,2mmm. This means, with 720lines, you have 33,9lines/mm. If you use a 4:3 format, your picture can be up to 34,5 x 25,8 and with 720lines, you have only 27,9lines/mm. But if you wont to use a original movie frame size, with only 16mm high, you have 45lines/mm.
So, if you use the 16:9 format with 21,2mm hight, the grid will be visible. Maybe we test next time also the SI-1300RGB, and maybe we create a 35mm solution (with our new GG) particularly for this cam together with a nice classical rounded "moviecam-like-housing" for the whole unit.

[Obin Olson]

Yes I will be designing a "movie-cam-like-housing" very soon ;)
so at 16x9 1280x720 you think that I will see the gg grain from wax?

[Rai Orz]

Obin, the "normal" wax technologie is what bosscreen use. You know the problems with bossscreen or intenscreen or so on. Microcrystalline wax has a fine grid, but the main different here is the very small space. But it is only the half way. Try it out. 1280x720 on a 37,6 x 21,2mmm frame size and you will see the gg grain.
Obin, lets work together, my company make not toys. And we not only have a HD 35mm solution, we have for example a low cost Follow Focus System for every still photo lens, with or without servo motors (And you need that with a 35mm DOF).
We also like to create a low cost HD CAM with 35mm DOF and other movie features. Today, we have contacted siliconimaging. Lets see...

[Jesse Rosten]

Rai -

In your previous post you said to use 90% paraffin wax and 10% bee's wax. Is this better than using 100% microcrystalline wax? What's the difference between paraffin and microcrystalline wax?

This thread is exciting. Can't wait to see more pics, Frank.

[Rai Orz]

Jesse, what is microcrystalline wax? I think a product name of Strahl & Pitsch. I can´t say what mixture it is. I know it is natural wax and we also tested it years ago. We dont had a way to change the mixture, so we make more tests with basic products like paraffin and bee's wax. We also make tests with chemical products.

[Frank Ladner]

Jesse: Microcrystalline wax is characterized by its small grain.

Check these links out:

http://www.britannica.com/eb/article...paraffin%20wax

http://www.calwax.com/products/Microcrys.asp

[Rai Orz]

Frank, thanks. We will check it soon, but the man who made our tests with microcrystalline wax is in vacation. So i can´t say details yet. The only thing i can say, with the other method our results are better.

[Bob Hart]

Rai.

I made a wax brew of 90%/10% and applied it between two oharadisks (glass CDs). Through a magnifier, the grain structure is about the same as the normal ground-glass dressed with 5 micron aluminium oxide powder water slurry.

The size grading of this grain structure varies across the disk which brings back the problem of variable density flicker I had with the plastic CD-R disks. This is why I went to optical glass.

Is there a subsequent annealing process to make the grain structure even across the screen?

Images through the rotating "boss screen" do not seem to be sharper but the colour seems brighter.

[Bob Hart]

Furthur to above, there are some images posted at "www.dvinfo.net/media/hart" titled "waxds002.jpg" or similar which are a test of a rotary wax composite disk. You'll have to put the address in by hand as it is not a link. I've forgotten how to do that href thing to embed addresses in the text.

[Matthew Miller]

Do any of you guys with the microcrystalline wax have like a 3 megapixel camera? Couldn't you use that instead of a DV camera to determine at what resolutions the grain becomes visible?

I have an 8 megapixel camera, and a Nikon Lens. Right now, I'm just starting to experiment with all the stuff I've been reading here. My first GG was just a piece of a white plastic bag stretched tight as a drum. Then I graduated to the school of rotating GGs and took a beltsander to a CD-R.

So I guess I should get my hands on this wax mix and start taking some hi-res comparison pictures of the different GG methods.

Obin,
I'm pursuing getting my hands on a nice wide angle Medium Format lens, just in case a 1280x720 sensor ends up seeing the grain too much when focusing on a square the size of 35mm film. The image projected onto the GG from a Medium Format lens should be over twice the size of what the 35m lens projects. And I've been reading all I can about depth of field to figure out if the medium format will be too different from a 35mm lens to get the 'movie' look we're all going for here.

[Bob Hart]

Matthew.

Although my tests with wax were shot with a rotating disk, I can advise that the grain structure was of a size similar to the AO 5 micron dressed optical glass disk.

I had no access to 3 micron so I allowed the 5 micron to wear down to exhaustion for a finer finish and partial polish-back. A polish-back seemed to confer a better clarity and brightness with plastic CD-R spacers.

With the glass, this is a bit tricky. If you leave the slurry in that state for too long, the glass hangs on the dressing sheet and gets gouges in it.

When shooting with the glass and CD-R, the spinning disk eliminated the grain as such but another effect in strong backlight, I describe as scintillation similar to snow or video noise, but of a finer texture, becomes apparent. It was subjectively like fine film grain.

It was more so with the glass disk until I went to the 5 micron and degraded the image even with the spinning disk. I theorise that the form of the abrasions in the glass and CD-R creates random pinpoint flashes of light under these conditions. It may be visible in the still image mtatk2f2.jpg in the background behind the guitar player. It was on the DVD.

You can see this effect in some of the still images even though the disk was moving. If some of the frame captures are enlarged heavily, you can see a pattern of blockiness of about 8 pixels area, where the DV codec is struggling with the high rate of subtle change between frames.

The wax disk originations dont seem to do this. Instead you see a pattern of slightly darker or lighter patches in the image more like very faded freckles. My theory for what it is worth is that whilst the wax disk that I have made does not yield a finer resolution, it does not introduce so much fine textured highlight variation in the image from frame to frame, so the codec does not have to play an aggressive averaging game with the resolution, therefore the image appears to be clearer. This is not of much help for fixed groundglasses. I think that whilst the grain structure is there i9n wax, it does not seem as sharply facetted like the glass texture is.

The beeswax portion of your brew will have to be carefully cared for as it darkens with overheating. It melts lower than boiling point of water and slightly before the paraffin and seems to have a tendency to settle out. Hold your glass above the brew in the heat for a while to preheat it before you drown it so you don't crack it. Likewise, don't haul it out into cold air in any haste.

[Martin Lindstedt]

I recieved my microwax about a week ago, and I've been trying different ways to minimize the airbubbles the last few days, however with no obvious success.

I've tried bonding the glasses at the sides and bottom, and then submerge it into the wax. What I can't figure out is why some airbubbles insist on staying between the glass. Even though I let the glasses sit in the hot wax for a while ( hell, I let it sit for two hours!! ). Any ideas anyone, to get those bubbles out??

One thing I discovered while experimenting, when I accedentaly dropped some hot wax into my pot with boiling water. When I was done for the day, and let the pot cool off, the wax solidified pretty evenly, on top of the water. The layer was too thick though, but if you poured just a small amount of wax into the boiling water, perhaps it could be carefully taken out once solidified?

[Bob Hart]

If there is a slight imperfection in the glass surface or a minute speck of dust, an air bubble will hang instead of moving up.

When making my composite disks, I found I had to place one disk in the melted wax, then lower the other disk into the brew at an angle so it became wetted and any bubbles moved off, then lower it on to the lower disk.

Because I kept the temp low, I was able to use a CD-R spindle to preserve alignment but getting the disks off it afterward was a problem.

I used pieces of cooking foil for spacers between the disks. TO prefvent them from moving, I glued them to the glass with PVC wood glue (I think you folk call it Elmers) on the outside surface and folded them under to provide the spacer. The glue washes off afterwards and the spare foil is trimmmed off.

Due to the method I used to figure and polish the disks, there was too much surface variation for them to be used back to back with any hope of a consistent thickness of wax between them.

I found this to be the cause of the variable density flicker I have previously described.

To melt the wax I have used an electic cookpot which has a sensor control somewhat like an electric frypan and will hold good temp control at or below water boiling point.

To clean your wax off the outside of the glass, use a fine razor or scraper blade, then use Preen trigger spray, then water and kitchen detergent, then methylated spirit or blue window cleaner.

[Justin Burris]

Just a thought here: when you get a chip in your windshield, and they come out to patch it, I understand that they put some sort of gel on the outside of the windshield where the chip is, then use suction on the inside which instantaneously sucks the gel into every little crevice. From what I have heard, once they have done this, you can't tell there was ever a chip.

I have to imagine this has potential for us. If we were to begin to submerge the two pieces of glass into the wax, then somehow apply suction at the top, thereby forcefully drawing the molten wax into the sliver of space between them...
I don't have any wax yet, so I am unable to try it, but Martin, if you are game, maybe this will be the ticket. Got a vacuum cleaner?