Gum Bichromate Print Question - Is this Solarisation?

ehsankiani · May 15, 2023

Hello.
I have just started with gum bichromate printing a month ago and learning my way. Wanted to ask about the issue in this image. I printed a negative on paper and waxed it to make prints. I used a 1:1 gum / potassium bichromate solution with added black poster colour. Different papers. Is the effect on the right side of the face due to Solarisation. I used a 4.5 minute exposure here. Posting the negative along with it too. Previous print did not have this effect.
Thank you for your feedback.

ehsankiani · May 15, 2023

Here is the previous print from the same negative. Same chemistry only that the brand of gum arabic and the paper was different.

Andrew O'Neill · May 15, 2023

I can only see what appears to be brushing issues... Are you smoothing it out with a hake brush?

koraks · May 15, 2023

Looks like part of the mid tones lifted off the paper. I'm no gum expert, but I understand that paper surface and sizing play a significant role here. Calvin Grier refers to "surface energy", but that turns out to be a rather involved and expansive topic. Basically it's about how well an emulsion will stick to a paper, and several factors influence this.

Andrew O'Neill · May 15, 2023

What koraks said. And... It's always best to strive for an even, thin coating.

Herzeleid · May 16, 2023

Use less pigment. Try to determine the ideal pigment load for particular amount of gum arabic. Ideal load will be different for each type of pigment.

Thayer Gum Tonal Inversion

Dwayne Martin · May 23, 2023

So many things can go wrong with gum. Could it be the wash is taking off too much pigment? I have had results similar to that when my washing was too aggressive. In my case now I let most of the development happen in the trays then I give it the most gentle wash passible to take the last bit of loose pigment off. If i don't do that then I get excessive pigment stains that are basically runs as it hangs to dry. All that said Ive seen plenty of videos where people basically spray the print with a hose and it seems to work out fine for them.

In my darkroom if my exposure time s in the ball park I can get a print developed in two trays in 30 minutes or so.

ehsankiani · May 23, 2023

Thank you so so much for all the replies. All of you are actually right. I learnt that I was washing too aggressively, pigment was a bit too much for that batch and I was washing with hot water. I am now using normal temperature water and gentle agitation. Does great.
As I said, this is just my first month into this technique and learning my way through. I am glad I stumbled across this forum. Long way to go for me so expect more queries and questions from the other side of the globe
Ehsan

Gum Bichromate Print Question - Is this Solarisation?

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