Curious Gum Problem

Jon Harwood · Jul 20, 2010

I have occasionally had a quite odd problem with Gum prints. Apparently randomly and with any layer I will get something that looks like a water stain on paper, that is there is no distortion of line or color within the blotch like shape but the border is outlined with a thin line in the color of the layer. This leads to a "Hail Mary" session with spotting brushes on the wet print as it develops and the retouching usually fails miserably. I have attached a detail from a work print that shows the sort of line I am describing. The last print I posted on the Hand Coated Wet Print Gallery had this problem but I was actually able to retouch it out.

Anyway if anyone has any idea why a problem like this would occur, please let me know.

donbga · Jul 20, 2010

Jon Harwood said:
I have occasionally had a quite odd problem with Gum prints. Apparently randomly and with any layer I will get something that looks like a water stain on paper, that is there is no distortion of line or color within the blotch like shape but the border is outlined with a thin line in the color of the layer. This leads to a "Hail Mary" session with spotting brushes on the wet print as it develops and the retouching usually fails miserably. I have attached a detail from a work print that shows the sort of line I am describing. The last print I posted on the Hand Coated Wet Print Gallery had this problem but I was actually able to retouch it out.

Anyway if anyone has any idea why a problem like this would occur, please let me know.

What paper are you using is my first question? Is the paper sized? Has it been pre-shrunk? We need more details.

Don

Jon Harwood · Jul 20, 2010

Don Bryant said:
What paper are you using is my first question? Is the paper sized? Has it been pre-shrunk? We need more details.

Don

The paper is Fabriano Artistico Hot Press sized with Glutaraldhyde.

I am happy to provide any other details.

donbga · Jul 20, 2010

Jon Harwood said:
The paper is Fabriano Artistico Hot Press sized with Glutaraldhyde.

I am happy to provide any other details.

Okay I size FAEW with glut. Tell me how you are doing that? From what I can see you's got a problem with the gelatin sizing or the internal sizing of the paper, but maybe not. Are you pre-soaking your paper? If so are you using warm or hot water?

How large is this defect? From looking at your image in the gallery I don't have a sense of the problem in the image (am I looking at the correct image?). Could you post a direct link to the gallery image?

Thanks,

Don

Jon Harwood · Jul 21, 2010

Odd Gum Problem

Don Bryant said:
Okay I size FAEW with glut. Tell me how you are doing that? From what I can see you's got a problem with the gelatin sizing or the internal sizing of the paper, but maybe not. Are you pre-soaking your paper? If so are you using warm or hot water?

How large is this defect? From looking at your image in the gallery I don't have a sense of the problem in the image (am I looking at the correct image?). Could you post a direct link to the gallery image?

Thanks,

Don

Hi Don,

I size with 50ml gelatin that has 2.5ml of absolute alcohol and .3ml if 2.5% glut. I apply it with a foam brush trying not to overcoat. Sadly the picture I posted doesn't give a very good indication of the problem. The size is usually aprox the radius of a lemon or orange but more irregular. Here's a direct link (I hope) to the gallery image.
http://www.hybridphoto.com/gallery/showimage.php?i=809&c=8
I managed to nearly eliminate the problem from the gallery image. With that image the problem occurred on the fifth layer (1-cyanotype, 2-indian yellow, 3-deep scarlet, 4 payne's grey to highlights, 5-payne's grey to the shadows. The problem occurred following the application of the fifth layer appearing in the clear white areas of the print or lightly tinted areas.

It is quite odd. If my information is not giving you the information you need, I will wait until the problem recurs and shoot a digital picture of the image in the developing water.

donbga · Jul 21, 2010

I size with 50ml gelatin that has 2.5ml of absolute alcohol and .3ml if 2.5% glut.

This makes no sense. What is the percentage of gelatin concentration? What is absolute alcohol? Vodka? If your gelatin concentration is 3% then your glut dilution is in line with what I use. I assume the Vodka is to reduce the sparkles.

I apply it with a foam brush trying not to overcoat.

That's sort of irrelevant - over coating that is. I size entire 22x30 inch parent sheets 10 to 20 at a time. It's more productive to do that. And I also probably put a thicker coating of gelatin on the paper than you do. For a 22x30 inch sheet I size with 38ml of gelatin, which is more than enough gelatin. The gelatin is also quite warm, between 135-140F.

The problem occurred following the application of the fifth layer appearing in the clear white areas of the print or lightly tinted areas.

If this is the case then you probably have a problem with the gum/pigment coating or a breakdown of the gelatin. Also 5 layers is really pushing the envelope IME. That many development cycles on sized paper can reduce the effectiveness of the sizing.

Jon Harwood · Jul 22, 2010

Don Bryant said:
This makes no sense. What is the percentage of gelatin concentration? What is absolute alcohol? Vodka? If your gelatin concentration is 3% then your glut dilution is in line with what I use. I assume the Vodka is to reduce the sparkles.

That's sort of irrelevant - over coating that is. I size entire 22x30 inch parent sheets 10 to 20 at a time. It's more productive to do that. And I also probably put a thicker coating of gelatin on the paper than you do. For a 22x30 inch sheet I size with 38ml of gelatin, which is more than enough gelatin. The gelatin is also quite warm, between 135-140F.

If this is the case then you probably have a problem with the gum/pigment coating or a breakdown of the gelatin. Also 5 layers is really pushing the envelope IME. That many development cycles on sized paper can reduce the effectiveness of the sizing.

Hi Don,

Yes the gelatin is 3%, sorry about not including that. The alcohol is reagent grade 200 proof lab alcohol. We can't get the high proof Everclear in CA. The 50 ml of 3% gelatin is nearly twice what I need to size 5, 8x10 image spaces on 11x14 Fabriano. In this there may be a clue I may be undersizing in response to reading that oversizing can create problems (per Livick). And yes, I heat the gelatin mix to 160F before taking it out to the studio to do the coating.

I try for three layers with tricolor and monochrome and usually that works. However this print needed additional correction, hence the additional layers of payne's grey.

Here's another possibility: The final layer of payne's grey was mixed to tint the shadows, so it was: .9gm paint, 4.5 ml potassium dichromate and 7.5 ml gum and a short exposure. That makes a really thick layer and perhaps the thickness combined with the fact it was layer five could have contributed to the problem. (Note-I weigh the paint but do not use the same measurements for each color. Relative weights are established to match the tinting strength of various pigments.)

If you have any suggestions I will greatly appreciate them. If not, I shall keep observing and try to return with more detailed information and better photographs of the problem areas.

Many Thanks!!

donbga · Jul 23, 2010

I heat the gelatin mix to 160F before taking it out to the studio to do the coating.

That's too hot for gelatin. I keep the gelatin hot and cover the gelatin mixing vessel with a piece of glass to prevent evaporation.

I try for three layers with tricolor and monochrome and usually that works. However this print needed additional correction, hence the additional layers of payne's grey.

How long do you develop?

Here's another possibility: The final layer of payne's grey was mixed to tint the shadows, so it was: .9gm paint, 4.5 ml potassium dichromate and 7.5 ml gum and a short exposure. That makes a really thick layer and perhaps the thickness combined with the fact it was layer five could have contributed to the problem.

Avoid thick layers of gum.

(Note-I weigh the paint but do not use the same measurements for each color. Relative weights are established to match the tinting strength of various pigments.)

Right.

If you have any suggestions I will greatly appreciate them. If not, I shall keep observing and try to return with more detailed information and better photographs of the problem areas.

Many Thanks!!

Keep printing you are doing pretty good, IMO - nothing is ever perfect. What strength is your dichromate? Your image looks a bit contrasty. Have you tried AD? I use about 15% AD. I could probably reduce that but I hate to recalibrate.

What are your coating tools?

Don

PVia · Jul 23, 2010

I don't size at all and I can get 5 layers with no staining. Normally I like to get it done in 3, but my last one took 2 more layers, one each in the magenta and cyan layers. Not my best print, but pretty decent.

I like Fabriano as well, and really like the soft press which seems to be sized a bit more and stiffer than the regular Artistico EW hot press. There's a bit of a canvas texture to it which may not be to everyone's liking.

I figure if Keith Taylor can mount on aluminum with no sizing, you can do the same thing even if you don't mount...but you may have to preshrink depending on the size of your print. If I preshrink it's only for 5 minutes in room temperature water, which for Fabriano seems to do the trick.

But everyone's experience is so variable with gum that it's hard to nail down or duplicate another person's workflow...

Here's the 5 layer print: http://www.flickr.com/photos/viapiano/4817062551/in/set-72157624234247830/

And here's a 3 layer with lots of whites: http://www.flickr.com/photos/viapiano/4676426612/in/set-72157624234247830/

Don, maybe you've seen these before so I apologize if I'm repeating myself. Have you tried any prints with mounting on aluminum yet?

Paul

donbga · Jul 23, 2010

I don't size at all and I can get 5 layers with no staining. Normally I like to get it done in 3, but my last one took 2 more layers, one each in the magenta and cyan layers. Not my best print, but pretty decent.

That's not the issue here specifically. Jon is sizing and he maybe having a sizing issue.

I like Fabriano as well, and really like the soft press which seems to be sized a bit more and stiffer than the regular Artistico EW hot press. There's a bit of a canvas texture to it which may not be to everyone's liking.

I preshrink my papers much more extensively but with cool water and parent sized sheets. I don't have a problem with internal sizing. I also develop my prints much longer than you do Paul. And if you do some physical development it's nice to work on a sized paper.

I figure if Keith Taylor can mount on aluminum with no sizing, you can do the same thing even if you don't mount...but you may have to preshrink depending on the size of your print. If I preshrink it's only for 5 minutes in room temperature water, which for Fabriano seems to do the trick.

You live in a very arid environment so I wouldn't count on your pre-shrink method to be valid for those who do not. But imobolizing the paper is certainly away to avoid that.

But everyone's experience is so variable with gum that it's hard to nail down or duplicate another person's workflow...

I'm not sold on the notion of no sizing.

Don, maybe you've seen these before so I apologize if I'm repeating myself.

Never apologize Paul - it's a sign of weakness.

Don

Jon Harwood · Jul 23, 2010

Don Bryant said:
That's too hot for gelatin. I keep the gelatin hot and cover the gelatin mixing vessel with a piece of glass to prevent evaporation.

How long do you develop?

Avoid thick layers of gum.

Right.

Keep printing you are doing pretty good, IMO - nothing is ever perfect. What strength is your dichromate? Your image looks a bit contrasty. Have you tried AD? I use about 15% AD. I could probably reduce that but I hate to recalibrate.

What are your coating tools?

Don

Good idea about overheated gelatin, I will keep it cooler.

My development times are typically 30 min. but can drop to 20 min. rarely and also expand to an hour or so.

The thick gum layer is a likely culprit with the problem so I will readjust the gum concentration when exposing for shadows.

I coat with a hake brush followed by a badger hair varnish brush.

I have been using 16% potassium dichromate and rarely have excessive contrast. However after 1 3/4 year of printing I am getting better at it, so I will keep an eye on contrast issues. I hate recalibrating also

Jon Harwood · Jul 23, 2010

PVia said:
I don't size at all and I can get 5 layers with no staining. Normally I like to get it done in 3, but my last one took 2 more layers, one each in the magenta and cyan layers. Not my best print, but pretty decent.

I like Fabriano as well, and really like the soft press which seems to be sized a bit more and stiffer than the regular Artistico EW hot press. There's a bit of a canvas texture to it which may not be to everyone's liking.

I figure if Keith Taylor can mount on aluminum with no sizing, you can do the same thing even if you don't mount...but you may have to preshrink depending on the size of your print. If I preshrink it's only for 5 minutes in room temperature water, which for Fabriano seems to do the trick.

But everyone's experience is so variable with gum that it's hard to nail down or duplicate another person's workflow...

Here's the 5 layer print: http://www.flickr.com/photos/viapiano/4817062551/in/set-72157624234247830/

And here's a 3 layer with lots of whites: http://www.flickr.com/photos/viapiano/4676426612/in/set-72157624234247830/

Don, maybe you've seen these before so I apologize if I'm repeating myself. Have you tried any prints with mounting on aluminum yet?

Paul

I size and preshrink. The preshrinking is critical in my situation and it really helps with registration. The Fabriano paper is well sized to begin with but I size it anyhow and typically have no problems. The odd problem I have noted could well be related to the heavy gum concentrations I have used for shadow exposures. I mix my own gum from powder, so it is extra thick already. I mix gum one part powder to two parts water per Demarchy as quoted by Christine Z. Anderson. This also leads me to think my issue may relate to too darn much gum in my high gum concentration mix.

donbga · Jul 23, 2010

PVia said:
I don't size at all and I can get 5 layers with no staining. Normally I like to get it done in 3, but my last one took 2 more layers, one each in the magenta and cyan layers. Not my best print, but pretty decent.

I like Fabriano as well, and really like the soft press which seems to be sized a bit more and stiffer than the regular Artistico EW hot press. There's a bit of a canvas texture to it which may not be to everyone's liking.

I figure if Keith Taylor can mount on aluminum with no sizing, you can do the same thing even if you don't mount...but you may have to preshrink depending on the size of your print. If I preshrink it's only for 5 minutes in room temperature water, which for Fabriano seems to do the trick.

But everyone's experience is so variable with gum that it's hard to nail down or duplicate another person's workflow...

Here's the 5 layer print: http://www.flickr.com/photos/viapiano/4817062551/in/set-72157624234247830/

And here's a 3 layer with lots of whites: http://www.flickr.com/photos/viapiano/4676426612/in/set-72157624234247830/

Don, maybe you've seen these before so I apologize if I'm repeating myself. Have you tried any prints with mounting on aluminum yet?

Paul

Paul,

I also meant to say if I've not already done so, I don't know why people got so bent out of shape about your tree print on the alt. process list. So far I've like all that you've shown on Flickr.

Don

PVia · Jul 23, 2010

Thanks, Don...I guess it's just like you were saying.

Gum is a lot of things to me. Sometimes I like to make a literal-as-possible translation and sometimes I like to let things fly, with paper negs, BFK, different color palettes, etc!

Jon Harwood · Jul 24, 2010

Don Bryant said:
Paul,

I also meant to say if I've not already done so, I don't know why people got so bent out of shape about your tree print on the alt. process list. So far I've like all that you've shown on Flickr.

Don

Yes both are really good prints. I think the tree is excellent and I am all for things going where they will with Gum. When I start a print I have a plan for it, but if interesting things happen I try to go with them. My latest pigeon portrait started life as a tricolor, but when the tricolor result wasn't so great I shifted to a monochrome technique that complimented the tricolor and saved the print. Whatever it takes to avoid the "last step" in gum printing, that is, "turn the print upside down and drop it in the trash"

R Shaffer · Jul 25, 2010

That is an odd problem indeed. It sounds like it appears while the print is still wet and developing. I have had issues when I dry the prints flat, especially on last layer or two for shadows. But for me it has been during drying and getting puddle like things. So I hang everything to dry now.

Do you dry flat? Maybe it is some sort of puddle ( extra damp area, not standing water ) edge artifact from a previous layer.

donbga · Jul 25, 2010

R Shaffer said:
That is an odd problem indeed. It sounds like it appears while the print is still wet and developing. I have had issues when I dry the prints flat, especially on last layer or two for shadows. But for me it has been during drying and getting puddle like things. So I hang everything to dry now.

Do you dry flat? Maybe it is some sort of puddle ( extra damp area, not standing water ) edge artifact from a previous layer.

Very very good point Robert. I always hang my prints to dry by a single corner.

Don

PVia · Jul 26, 2010

I now dry my gum layers with a hair dryer set on low.

As soon as the print is finished developing, I let a trickle-stream of water wash over it for a short time up to about 15-30 seconds. I do this in a tray and the paper sticks to the bottom of the tray.

Then I give it a shot with the dryer until the surface is matt looking. Only takes less than a minute and no problems with wet areas running, and prints remain crisp and sharp.

Curious Gum Problem

Privacy & Transparency

Privacy & Transparency