Mold coating problem - bad surfactant?

Dichromated Gelatin.
holomaker
Posts: 772
Joined: Wed Jan 07, 2015 8:01 am

Mold coating problem - bad surfactant?

Post by holomaker »

Hi guys, the cooling of the gelatin should only take 20mins or so to solidify, an easy test is to place a small puddle on your mold's surface, check it after while to see if it resists you pressing down on it, when ready it will be rubbery and should peel off the molds surface easily. You dont want it to get to freezing point as it will crystilize and will stay that way when it dries ........

Joe is correct about the ammount of AMDI needed in your film for 532nm.

here is an older picture of the color you plates should be.
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holomaker
Posts: 772
Joined: Wed Jan 07, 2015 8:01 am

Mold coating problem - bad surfactant?

Post by holomaker »

MilanKarakas wrote:I think that my problem is not mold alone, nor surfactant alone. There are mixture of beginner's problems. This mix formula is pretty bad: 100:5:0.5, and 100:5:0.5+Rh6G, so both showing no trace of the dichromate, but it is somewhat sensitive (got some rainbow after 5 minutes of exposure, also tried 10 and 20 minutes, but no differences).

I think your ratios are off quite a bit...

for 532nm film, my recipe is; 5grams AMDI, 15 powdered gelatin, 100+ ml of distilled water. As Joe suggested forget using the dyes for now.
If you can pack 5% AMDI into your film (befor it crystalizes), that will alone increase sensitivity greatly !
MilanKarakas

Mold coating problem - bad surfactant?

Post by MilanKarakas »

holomaker wrote:
MilanKarakas wrote:I think that my problem is not mold alone, nor surfactant alone. There are mixture of beginner's problems. This mix formula is pretty bad: 100:5:0.5, and 100:5:0.5+Rh6G, so both showing no trace of the dichromate, but it is somewhat sensitive (got some rainbow after 5 minutes of exposure, also tried 10 and 20 minutes, but no differences).

I think your ratios are off quite a bit...

for 532nm film, my recipe is; 5grams AMDI, 15 powdered gelatin, 100+ ml of distilled water. As Joe suggested forget using the dyes for now.
If you can pack 5% AMDI into your film (befor it crystalizes), that will alone increase sensitivity greatly !
You are right. I can barely see some yellowish tinge at strong light and white paper behind (doubling absorption).:
100:5:0.5
100:5:0.5
If someone doubt that there are no emulsion at all ( :D ) here is the test with 36 W UV curing lamp (for nail gel purposes).:
Left one underexposed (10 seconds at 15cm), middle one about okay (30 second at 15 cm), and right is attempt to put white paper with print on it - big mistake due to blue fluorescence and exposure of 120 seconds.
Left one underexposed (10 seconds at 15cm), middle one about okay (30 second at 15 cm), and right is attempt to put white paper with print on it - big mistake due to blue fluorescence and exposure of 120 seconds.
All plates, forgot to apply dark reaction, only middle about 30 seconds in dark. About 15 seconds in very dilute Kodak T-max fixer, then 10 seconds washing with hot water from boiler (tried even two minutes, but gelatin is very well cross-linked!). Green triarylmethane dye ("Green S", E142, food coloring) is added just to inspect how much gel is cross linked.

This test is done because of futile work with such low concentration of dichromate, and in the same time test for future work with negative PCB photoresist. It is more resistive to acid than one I use (positive). Just need to change photo mask from positive to negative. Also, there is option (maybe one day) with 405 nm diode, and 'printing' photo directly by scanning over the copper plate (PCB) covered with some gelatin/dichromate mix.

Thank you, Dave for very good advice! Right now room cleaner running and after hour or two, it will be ready for mold coating. Tomorrow will be ready for veil coating (after 24 hours it cleans pretty well whole room, almost no laminar flow needed).

Here are pictures of very improvised pseudo-HEPA filter:

http://www.flickr.com/photos/milan_karakas/8069549804/

http://www.flickr.com/photos/milan_karakas/8069553000/

And, difference before and after running of about 1 hour.:

http://www.flickr.com/photos/milan_karakas/8069582520/

I hope someone of you will adopt this method and improve air quality for laser holograms and gelatin work.

Best--
m--
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