Need help to improve mid and dark tone details in gum printing

Debanjan

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Dear All,
I've just started with Gum Bichromate printing and this is also my first foray in darkroom printing. I seem to be getting decent details in highlights but the mid and dark times are usually muddy and I need to subject the prints to water trickles to bring out some details at the cost of loss of contrast in general. With my UV bank of BL tubes, the exposure of 4 minutes for the first coat brings out 60-70% details and i go up to 4 coats with successive reduction in exposure times. Attached is an image with 2 coats -- lime yellow first coat followed by ivory black second coat. Can you please suggest how to improve upon the limitations am experiencing? Thanks in advance and best regards, Debanjan
 

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koraks

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I think your best bet is to get in touch with Bob Carnie; he hangs out a lot on the largeformatphotography.info forum. He has been doing a lot of gum-overs in the past few years and seems to have settled on it as one of his favorite printmaking approaches. AFAIK he mostly does gum over kallitype or Pt/Pd - which already tells you that he has 'solved' the problem of dmax by using a different process for the contrast and then uses gum for coloration.

In the brief foray I did in gum bichromate I noticed that it is indeed difficult to get a solid black; it can be done, but it needs several high-contrast layers (high pigment load). I found it very difficult to combine high density with smooth tonality. I think gum-over-somethingelse offers better control.
 

radiant

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I was on two day course just this weekend on gumprint and noticed the same "issue".

I got one print with a bit more deeper black by making one layer with lamp black with short exposure. I didn't try this but could it increase density of lamp black even more if the mixture would be 1:1 with dicromate + pigment without the one part gum arabic ..
 
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Debanjan

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Thank you @koraks and @vedostuu. I did go through the several youtube videos that Bob had shared and they were informative and helpful. I also got the guidance to try out multiple layers with varying pigment / dichromate and exposure mixes to develop the highlights, midtones and shadows. I would say am getting some better results with the said approach. Attaching a sample for your review / comments (straight shot from the mobile - no adjustments). Thanks again.
 

koraks

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Yeah, that looks similar to my attempts. I suppose if you build some more layers you'll get more density. And then of course work on the highlight layers as well.
Btw, I remember I ran into trouble with more than 3 layers as additional layers would have poor adhesion. Might have been related to my gum or pigment, I don't know. By that time I decided I didn't want to pursue this process further. Maybe some day.
 

removed account4

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HI Deb

I am an expert by no means but from my limited experience with this process I've come to realize that its best to do a layered approach where you put down a base layer and build up on it with mid-tones and then having layers where you have negatives specific for highlights. I've done some straight gums and some with cyanotype as a base layer, and I've read reports of people putting down 10 or even 20 layers to build up density and tonality .. I'm not that crazy, i've only done a couple not more than 3 or 4, but there's always tomorrow
I love the image you just uploaded the staircases seem to float off the building !
Have you tried using a smooth surfaced paper for your images, maybe one of your problems is the paper you are using isn't suited for what you want to do, and the combination of the texture and softness is problematic. I've had good luck with Bristol, and super smooth Velum ... not sure if you can get those in your neck of the woods or amazon, it might be worth a trip to the art store to see.
best of luck mastering this difficult process
John
 
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Debanjan

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Thanks @koraks. I have gone upto 4 layers so far. Gum / Pigment wise things are falling in place and no issues related to adhesion. Yes - highlights need to be more controlled for sure.
 
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Debanjan

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Thank you @jnantz for the encouragement.

Yes - the paper could be an area to focus. I could get hold of only cold press Fabriano / Canson at the moment and these all have textures. I will definitely try to suit the paper with the mood of the image - a very helpful tip indeed. Thanks and regards.
 

radiant

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Here is the print I was talking before. Last layer was lamp black just for the shadows (normal mix, short exposure) - I know my alignment wasn't that succesful :



Here is mine single layer with lamp black:

 

radiant

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This one is two-layer, the shadows become more darker from applying orange layer for whole print. The orange layer was a really short full (no negative) exposure but still it sticked really hard and I had to spray like maniac to wash it away (only to keep in horizon):



It looks pretty OK'ish on screen but in reality it is way too light to be displayed.
 
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Debanjan

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At the moment am using Fabriano Artistico Cold Press (Studio Grade) 300gsm paper .. Hahnemuhle platinum rag is not that easily available but am on the lookout for hot press versions or papers that have a smoother appearance. Here's another example of what I could manage with layering as @koraks suggested
 
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Debanjan

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I really like it and thanks for the idea regarding the Orange colour ! Really innovative. Thank you for sharing. Something to try for sure
 

radiant

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Debanjan said:
I really like it and thanks for the idea regarding the Orange colour ! Really innovative. Thank you for sharing. Something to try for sure
Click to expand...

That was nowhere innovative compared to what some of the course students were making. I couldn't understand how they grasped such complex methods so fast.

Debanjan said:
Need to try Lamp black .. so far I was sticking to "Ivory Black" .. Thanks for sharing
Click to expand...

Our teacher said he avoids Ivory Black, but I cannot remember why. Was it so that it was difficult to wash.. Cannot remember.

BTW: what is the manufacturer of your colors?
 
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Debanjan

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Currently am using Mijello Mission Gold watercolours. It's a Korean company is what I know. Yes - the Ivory Black does take a while to wash properly but nothing alarming so to say.
 

nmp

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Looks like you have nailed it with this one...it's the best I have seen in terms of Dmax and tonal rage. I kind of like the texture - suits well to this process.

:Niranjan.
 
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