U of S | Mailing List Archive | alt-photo-process-l | Re: Newbie Gum fun Continued

Re: Newbie Gum fun Continued

Hi Katharine

Thanks for the info. I'll test the Arches paper tonight with the boiled up shrinking and let you know how I go.
I haven't used any hardeners as yet because I can't seem to find any here in Perth, still looking..

The lamp black is Windsor and Newton, any suggestion for another type of black tube paint from them you would recommend in getting a nice jet black colour? Ivory black or Neutral tint by W&N perhaps?
The gum solution was 33%. I used 5ml of that with 2 small dots of Windsor and Newton lamp black. With 5ml Potassium Dichromate Saturated Solution.
I'll try my hand at reducing the lamp black and see what I get.

I'll try the foam padding under the paper to get the maximum contact of the negative and glass.

Another question I have is with the Potassium Dichromate, is it worth reducing the saturation of this to get a longer tonal scale? What would I be missing out if I reduced it? 
I guess time for exposure would be more, that is if I used exactly the same amount of gum and pigment, as I did for the same saturated solution of Potassium Dichromate.
My understanding would be to change the negative using the photoshop curve to get the full graduation of tonal scale and leave the Potassium Dichromate saturated as it is.
The only 2 variables I should worry about are the Gum and Pigment. Is this assumption correct or partly correct or just try it and see where it takes me :)


 On Tue Apr 24  1:55 , Katharine Thayer <kthayer@pacifier.com> sent:

>Hi Jacek,
>Perhaps I wasn't clear in communicating my experience with Arches  
>paper before.  There are two issues:  (1) in my experience, Arches  
>paper as now formulated can't be printed unsized because of  
>speckles.   If you got a good result by shrinking it with boiling  
>water and printing unsized, that's interesting, and inconsistent with  
>what I've seen before. The rule with gum is, use whatever works; if  
>boiling water works for you, go for it. My experience has been that  
>treating with very hot water just messes with the internal gelatin  
>size, but that's the thing about gum, we often get contradicting  
>observations.  (2) When sized, my experience is that the sizing for  
>Arches should be kept below 140 or I get speckles in the sized paper,  
>but as people are always saying, your mileage may vary.   I harden  
>with glyoxal.
>About your problem with incomplete contact, it may not be that the  
>glass isn't heavy enough; your problem may be on the back side of the  
>paper.  When I first started printing gum, I had the same problem; I  
>had a piece of smooth wood on one side of the paper and a piece of  
>plate glass holding the paper to the wood, but I had areas in the  
>print where it was obvious there was inconsistent contact.  I got  
>some interfacing from the fabric store, sort of a webby stuff, but  
>foam rubber or something similar would probably work as well, to  
>place between the wood and the back of the paper, and that's all I've  
>used ever since to get good contact.  It holds the paper securely  
>against the glass.
>Two pea-sized pieces of lamp black in how much gum?  What brand of  
>lamp black?  I might be inclined to guess just on general principles  
>that you may be using too much pigment,  only because in my  
>experience beginners almost always use too much lamp black to start.   
>Lamp black is a very powerful pigment; a little goes a long ways.   
>Try cutting your lamp black by half by adding more gum; if you still  
>get a dark black where you want a dark black but no staining, then  
>the staining was probably due to too much pigment rather than  
>insufficient sizing.  I've got an example on my website that shows  
>the difference between way too much lamp black and half that much, if  
>you want to compare what you're observing:
>I coat paper in daylight or under a 60-watt tungsten light with no  
>problem; a safelight isn't necessary.  Just don't do it in direct sun.
>On Apr 23, 2007, at 9:17 AM, Jacek Gonsalves wrote:
>> Hi all,
>> Well I finally took the plunge on the weekend and did my first ever
>> print in gum.
>> The results were...well something actually came up and I can see I  
>> have
>> a long way to go! :)
>> I used W&N lamp black tube, found I couldn't weigh it on my scale  
>> when I
>> squeezed 2 pea sizes out, nothing registered on the scale! :)
>> The paper itself got stained perhaps of too much pigment or because I
>> didn't add enough gelatin to the paper?
>> My paper seemed to have curled and the negative seems to not have sat
>> comfortably on it, even with a heavy glass on. I might have to put
>> something heavier or try keeping the paper flat when drying with  
>> all the
>> preshrinking and gelatin. Perhaps I can find plans on the net to  
>> build a
>> Contact Frame?
>> The Arches paper Smooth 300gsm, I had an issue with dotted speckles, I
>> found that the water preshrinking I used wasnt that hot. The water
>> couldnt penetrate the whole paper, therefore getting speckles in the
>> paper. Also the fact I was preshrinking for only 10 mins.
>> I used this paper to develop a print, and the part where you can  
>> see the
>> dotted speckles, has been stained with the lamp black pigment, the  
>> rest
>> seemed unstained.
>> I ended up using boiling water to preshrinking another batch of the  
>> same
>> Arches paper, and I got no more speckles! Though I might have damaged
>> the actual manufacturers hardening of the paper? Also it really  
>> gave off
>> fumes with the boiling hot water, I had to take it outside.
>> I tried a batch, Katharine suggestion of below 140F(60C),  
>> unfortunately
>> it still has the dotty speckles. I changed the water at least 4 times,
>> their still there! :(
>> Reading the Altlist I see some people just use lukewarm water to
>> preshrinking?
>> Also what paper do you use and how do you preshrinking it? With  
>> boiling
>> hot water, lukewarm water etc?
>> I also tried Acquarello Fabriano cold press with no preshrinking, a
>> brushed on gelatin on one side. Developed the paper and got staining.
>> Perhaps another gelatin coat would have fixed it or less pigment?
>> I'm not using any hardners in my gelatin and perhaps that could also
>> account for the staining.
>> Is a RED safelight, ones used in the darkroom safe to use when coating
>> gum? What do you use?
>> More to come...
>> Thanks
>> Jacek