Variable contrast Azo paper

[Photo Engineer]

After due deliberation, I have figured out a way to make a variable contrast contact paper similar to grade 2 and 3 Azo.

My question is this.... Would there be any use for it?

It would use UV and blue light to get the 2 contrast grades.

PE

[David A. Goldfarb]

It sounds like more trouble than it's worth if the range is from grade 2-3. Make it from grades 1-4, and then it starts to sound more interesting.

On the other hand, if you're coating your own anyway in small quantities, it seems that one could always just coat to the contrast one needs.

[jgjbowen]

PE,

I want to encourage your work in this area....But, as an Azo user, I have both a blue, Zone VI, cold light and a UV "The Cold One" Azo head. If I had to change heads back and forth in order to vary the contrast, I would probably shoot myself or turn to platinum printing.

How do we practically change light sources from UV to blue?

Most Azo users would likely use grade 3 and an waterbath to vary the contrast from grade 2 to grade 3. We as a group would probably much prefer a straight grade 3 and a grade 4.

[Scott Peters]

Not necessary....just grade 3 with water bath is acceptable to get down to lower grades. Grade 4 would be nice to have around for those rare occassions though....

Changing lights seems like more trouble than its worth. I wonder how the azo testing is going......

[Photo Engineer]

The light could be a mixture of UV and visible (Blue) with a UV filter that moves in and out of the beam and a yellow filter to vary the UV content vs Blue content.

With some thought, I think I could make a grade 1 - 4 but it would be a LOT harder, so you can comment on that as well. I have made both extremes of paper so it is not impossible.

As for Azo, that is a Kodak trademark so testing of Azo is not what we should be asking. Lodima is a trademark of M&P and I am calling mine an "Azo Like" paper. AFAIK, you have to look to M&P or any of their authorized test individuals for comment. Last I heard, their tests were going poorly as read from their web site.

From my reading of Michaels own account, I don't think it is possible for them to make a usable Azo type paper from their current formula. I've commented on that before here on APUG. I do wish them well though. However, I have no idea of the capability of the engineers they have hired to do this job.

PE

[rmazzullo]

Hello all,

You can get UV LEDs and Blue LEDs very cheaply nowadays, and can create rows or banks of each in the same "lamp head", and switch the rows on or off as needed, to vary the mix of UV and Blue. (There are even different shades of blue, depending on where you get them from. Solid state, and instant on / off. The only caveat is that you cannot look into the UV light.

It might be possible to 'dim' one side or the other as needed, but there is some extra circuitry (not hard to build) that might be required to do this.

Thanks,

Bob

[Scott Peters]

Ok, grade three then for A_O like paper...hopefully we will hear about the 'new A_O / Lodima testing soon.

[Shawn Dougherty]

Speak for yourself man, grade 2 is a must. Shawn

[skillian]

What difference does any of this make unless this paper can be commercially produced? Maybe it's easier to hand-coat than it sounds, but all this talk about silver chloride papers that I can't have is like giving me a case of "Azo blue balls".

[Photo Engineer]

Scott;

Try imagining it being commercially produced and then re-post.

Thanks.

PE