Gum bichromate speckling

Dwayne Martin · Aug 13, 2022

Hi Gang, anyone ever try to repair pigment speckles on a gum print? If they were wide spread I wouldn’t bother but I have a few prints with a speck here or there or a small group of them were my gelatin didn’t penetrate properly. I was thinking of trying a tooth pick with ferri on it.
I’m thinking if I over do it I can touch it up with water color maybe. Anyone ever tried this?

D

koraks · Aug 13, 2022

Dwayne Martin said:
a tooth pick with ferri on it

It's not silver based, so I'd expect the ferricyanide (if that's what you mean) not doing anything except add a yellow stain.
How about taking a hypodermic needle or an exacto knife and scrape it off? You could then touch up the spot with a little gelatin solution to fix the unevenness of the surface finish that will result from scraping.

Dwayne Martin · Aug 13, 2022

koraks said:
It's not silver based, so I'd expect the ferricyanide (if that's what you mean) not doing anything except add a yellow stain.
How about taking a hypodermic needle or an exacto knife and scrape it off? You could then touch up the spot with a little gelatin solution to fix the unevenness of the surface finish that will result from scraping.

That might work but the problem is the speckles are deep in the paper while the image itself sits on top of the gelatin. I suppose I could test and see what might bleach the water color pigment on a junk print and see if there is a path forward that way.

revdoc · Aug 13, 2022

So these specks are places where pinholes in the sizing let the pigment get into the paper itself? I can't think of a cure for that, other than covering them. At a guess, I think you might have to paint over them with opaque white, then with watercolour to match the surrounding tone.

Andrew O'Neill · Aug 14, 2022

Is it a must to size your paper? I use Hahnemuhle PR, without size and gum prints looks great.

Dwayne Martin · Aug 14, 2022

koraks said:
It's not silver based, so I'd expect the ferricyanide (if that's what you mean) not doing anything except add a yellow stain.
How about taking a hypodermic needle or an exacto knife and scrape it off? You could then touch up the spot with a little gelatin solution to fix the unevenness of the surface finish that will result from scraping.

You were right the ferricyanide had no real effect.

revdoc said:
So these specks are places where pinholes in the sizing let the pigment get into the paper itself? I can't think of a cure for that, other than covering them. At a guess, I think you might have to paint over them with opaque white, then with watercolour to match the surrounding tone.

Thanks, I think I will give that a try.

Dwayne Martin · Aug 14, 2022

Andrew O'Neill said:
Is it a must to size your paper? I use Hahnemuhle PR, without size and gum prints looks great.

I have had nothing but bad luck with that paper. It works better for me when I size it though. Like you lots of people swear by it. I'm not sure how many coats you're using but i'm using 6 to 8. I'm using a hot pressed paper called "Fluid 100". Of the papers I have tried I get the best results with it.

Andrew O'Neill · Aug 14, 2022

Dwayne Martin said:
I have had nothing but bad luck with that paper. It works better for me when I size it though. Like you lots of people swear by it. I'm not sure how many coats you're using but i'm using 6 to 8. I'm using a hot pressed paper called "Fluid 100". Of the papers I have tried I get the best results with it.

I do three, sometimes 6 or 7 layers. What pigments are you using? Some can stain easily...

Dwayne Martin · Aug 15, 2022

Andrew O'Neill said:
I do three, sometimes 6 or 7 layers. What pigments are you using? Some can stain easily...

Mostly Windsor & Newton. In this case it’s not a staining problem. I’ll post some pics I just have to resize them to post here…

Dwayne Martin · Aug 15, 2022

This is what I'm talking about. Not a big area but enough to warrant retouching them somehow.

revdoc · Aug 16, 2022

In which layer do they first appear? I've had specks like that from small particles of solid dichromate that found their way into the sensitiser.

koraks · Aug 16, 2022

Dwayne Martin said:
This is what I'm talking about.

Calvin Grear calls it 'speckling', but I suppose others might call it staining and still mean the same thing, even though it's not a uniform stain like remnants of dichromate etc.
Have a look here: https://thewetprint.com/wp-content/...ical-Guide-to-Gum-Printing-Introduction-2.pdf
Page 17 (which is actually page 25 of the pdf...)

Anyway, my initial advice still stands: I'd scrape them out of the paper with a thin, sharp tool, and then repair the zit by applying a small dab of gum, perhaps with a little pigment added to match the surrounding tone.

Nice print BTW.

Dwayne Martin · Aug 16, 2022

revdoc said:
In which layer do they first appear? I've had specks like that from small particles of solid dichromate that found their way into the sensitiser.

Not sure actually, that print has about 5 coats of lamp black on it so either it built up slowly or I just didn’t notice for a while.

Dwayne Martin · Aug 16, 2022

koraks said:
Calvin Grear calls it 'speckling', but I suppose others might call it staining and still mean the same thing, even though it's not a uniform stain like remnants of dichromate etc.
Have a look here: https://thewetprint.com/wp-content/...ical-Guide-to-Gum-Printing-Introduction-2.pdf
Page 17 (which is actually page 25 of the pdf...)

Anyway, my initial advice still stands: I'd scrape them out of the paper with a thin, sharp tool, and then repair the zit by applying a small dab of gum, perhaps with a little pigment added to match the surrounding tone.

Nice print BTW.

Dwayne Martin · Aug 16, 2022

Yeah you’re right I actually learned to call it speckling by reading Calvin’s book. Before I ever had the problem actually. I agree with you on the repair method. My buddy Patrick Robert James told me to use a tiny drill bit instead of digging, which is a great idea.

koraks · Aug 16, 2022

Oh yeah, that sounds like an interesting approach. I've got one of those generic press stands for a Dremel tool; it would be pretty easy to quite precisely mill away some specs with one of those tiny carbide drill bits. Good idea!

Gum bichromate speckling

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