Adjustment Curves Layer for the DN of the multi-layer gum prints?

I am interested in doing tests with your software Dan, say starting with1st curve till it seems good for HL-MT then adding the MT-SH & see where it takes one.
Have to get the light tones up in density as I notice generally that there is too much contrast in the HL, the SH tends to bung up without enough DMax requiring a 3rd or even 4th layer.
It could be that the inkjet printer does not lay down enough ink in the lightest area of the neg that contributes mainly to that issue.
If some more users are interested in taking part this would be great.

 

I have been printing gum over palladium for a very long time and extensively..

Gum is a wash off process and IMHO any negative will work , you just need to control the wash off period. With this said I use the same curve for gum that I do for Palladium and if I feel I want to hold the gum more in areas I flatten the curve to allow more exposure to come through.. It is a hardening process and therefore I think complicating the negative thought process is not needed.

Here is a sample of a duo tone gum over the palladium. All three neg's were made with the same profile curve that was established for palladium layer.
Palladium Coating
1. Palladium image is a full scale rendition of the scene from shadow to highlight and all in between.

Gum Coating
2. Blue colour is exposed using a shadow negative - which is done in blend if and taking only the lower values and printing
3. Orange colour is exposed using a mid to upper highlight negative - which is done in blend if and taking only the upper values and printing.

Where there is no exposure in either colour or gum negs the pigment can be washed off and the exposed hardened areas are left behind. So if you think about Gum this way you will come to the same conclusion that I have is that as long as it is a negative that has the characteristics you want then it will work.

I think of the movie Karate Kid when making gum overs ... the palladium is a WASH ON process where the noble metals are introduced to the paper , and the gum layers are a WASH OFF process where the unwanted gum is washed off with water.

I have studied , all the books, my hero's are Stephen Livik , Sam Wang and Christina Anderson, and if you delve into the process deep enough you may find sage words in what I have just wrote.
Once you see this aspect of the process the faster and better you will grasp multiple negs and the Gum process.

just my two cents.

Bob

 

The issue with multiple negs requires too much attention to the registration problem when one has a lousy punch system.
Pros, they have all that is required in house but us mortal cheapskates fiddle about.

 

I think the issue is with the operator not figuring out registration rather than the system to achieve it, which is not that difficult and certainly not expensive. I would argue after 10 miss registered prints fiddling about you have the cost of a simple punch system with the waste.

 

I use four thumbtacks, and my registration is spot on.

 

I use an office hole punch and some screen printing registration pins. Total cost about $25 and it works perfectly.

 

I am not sure I fully understand....are you trying to do a multi-layer single color (like black and white) or a multi-color print like a full RGB image. The two cases will have to have completely different approaches, no?

:Niranjan.

 

Dan, OK. So it is a monochrome gum print using multiple iterations of (coat/expose/process) steps, using the same negative.

Raises more questions for me:

1) what is the purpose of multiple layers - is it to increase the shadow density incl. Dmax? Like what Irving Penn did with his pt/pd's.

2) why the same negative? You still need to align the negative every time regardless of whether you use same negative or not. Then why not tailor each layer with its own negative.

Am I missing something here?

:Niranjan

 

I use registration marks in the four corners printed on my negatives and don’t have registration issues. It doesn’t cost me a dime. If I’m printing straight from a camera negative, I use the four corners of the negative. If you don’t want them to show in the final print, and keep a feathered edge, just place them in the far corners and drop a dab of emulsion out there, not connected to your feathered edges. Then trim them off when you’re done.

As for controlling the density of multiple exposures, I use the same curves for each pass and adjust the chemistry and exposure times to adjust my density. I find that is a better approach for controlling highlights and shadow density independent of the mid tones. Double the pigment and half the time for shadows, and half the pigment and double the time for highlights, as a rough guide to get you started. You really have to experiment to figure out your system.

 

At present I like the single neg approach as the neg never leaves the glass till complete.
The paper after preshrink gets two double side alu tapes and punched (office punch) and this gives pretty good registration so introducing multiple negs for me is a pita.
I think getting a 1st curve more or less close for HL-MT adding the 2nd layer and then measureing the result for fine tune of 1st neg. curve might be a direction.

 

I am sorry but are you suggesting the pt pd after a thick layer of pigmented gum.???? so how does the pt pd penetrate into the paper, is it sitting on top of the gum?? enquiring minds need answers.

I have tried multiple coatings and using multiple negs with single process before with disastorus results , I need to see more of your prints and workflow to understand what you are trying to say here.

I use different methods to get the effects I want but I certainly do not think one negative can do what I do with two , three or even sometimes four.

 

I make a lot of negatives and am completely familiar with it and I am still trying hard to understand how a single negative with a wash off process will give you what you want.. It is a hardening wash off process and what
you are suggesting or Dan is suggesting makes absolutely no sense to me. I print gums every month and am quite aware of the effect of water on the gum pigment Ammonium Dichromate mixture after it has received exposure to UV light.

 

Thanks, Dan for the elaboration. I get the scenario now, sort of. I am still learning.

Are you familiar with works of Keith Taylor (of Cy DeCossy fame)? They are the most photo-realistic gum prints that I have come across. Wonder how he does it. He uses C, M, Y layers apparently but no idea of multiple applications of the same color to get those dark shadows:

https://www.cydecosse.com/collections/san-ambrosio-market-color/

:Niranjan.

 

Interesting , does the gelatin sit as a layer like carbon transfers do or does the emulsion sink into the gum layer.

 

He does three layers with cyan, magenta and yellow as most tricolour gum printers do.

 

Thanks Bob. No need for a K layer then, as the conventional printers do.

I love your work too...

 

I actually use a palladium layer for the detail and use cmy on top, I suck out density on the palladium layer in colour regions so full colour can come in.