Re: Unknown area in Gum printing?
Thanks for that. I have to readjust how I brush the coating. Change the pigment concentration and get some hardening. The hardener, I just spent a whole lot of time sourcing it and came up with only one company only selling 5 litres of formaldehyde and nothing less, one of the reasons I'm reluctant to get it. I cant even get it from overstate or overseas with all the security regulations :| Though I havent looked for others like Chrome alum or glyoxal, I think its best if I do.
On Fri Apr 27 3:04 , Katharine Thayer <email@example.com> sent:
>Jacek, this is way underpigmented for lamp black, so as I guessed
>earlier, pigment stain due to overpigmentation is definitely not your
>problem here, as you might have seen if you'd checked the comparison
>images I pointed to for lamp black. I'd agree with Judy; your
>stain in highlight areas (and I'd definitely call that pigment stain
>in the highlights on the Arches) is probably a function of the
>unhardened size. It's interesting that the unhardened gelatin seems
>to work better on the Fabriano paper. I agree that tray clearing is
>probably better than spraying the clearing agent on.
>On Apr 26, 2007, at 10:32 AM, Jacek wrote:
>> Hi all,
>> If you want me to upload more detailed images of each let me know.
>> The negative is made by an imagesetter, I used a 2% increment grey
>> scale file made in photoshop.
>> This is the Arches w/c 300gsm smooth paper.
>> Print looks very light.
>> The first one, 4min, its a bit messy with me adding a clip on left,
>> in the middle of the paper when I had to dry it, it took some w/c
>> out :|
>> The numbers can be distinguished.
>> 16to20% above it, not so sure what I did there possibly sprayed the
>> potassium Metabisulfite a bit too close?
>> 0 to 30% seem fine to me, though after that things start looking
>> messy, there seems to be a vertical light smudging, plus yellowing
>> from 86% to 100%, possibly needs more potassium metabisulfite.
>> The next, 6 mins.
>> The print start looking smudgy at 52% onwards. Perhaps too much
>> yellowing from the dichromate stain?
>> The bottom 92% onwards was at the edge of the paper and there
>> probably wasnt enough coating there, thats why it looks uncoated
>> and speckly.
>> The next 8 mins.
>> The clips there again in the middle :|
>> You can clearly see that with more time, the 10% is darker than the
>> 4mins one.
>> Same sort of vertical yellow streaking/smudging in the shadows.
>> Next image:
>> Fabriano Acquarello 300gsm
>> First one, 8min.
>> The clip smudged the paper in the middle?
>> From 0 to 40% it looks ok.
>> Then It starts getting discoloured after that, with yellowing on
>> the print. The scan your looking at doesnt seem to represent in
>> colour to what the print does.
>> The next, 12min
>> This seems to look ok from 0 to 32%. From there it looks dark and
>> The colour doesnt seem to be constant in the shadows. It has
>> streaks of lighter tones?
>> I think I could be overexposing too much?
>> Possibly need to add more gum?
>> Relative humidity is 60%-65%, Black Light Blue tubes 18 watts.
>> Thanks everyone for the help, I appreciate it! :)
>> On Thu Apr 26 21:11 , Katharine Thayer firstname.lastname@example.org> sent:
>>> Hi Jacek,
>>> One initial observation is that pigment stain will affect the
>>> highlights and unexposed areas of the paper as well as the shadows,
>>> so if your highlights and the unexposed parts of coated areas are
>>> clear, then pigment stain probably isn't an issue. And from the
>>> description ("a small smudge") of the amount of lamp black you used,
>>> it seems unlikely that overpigmentation is an issue either. The
>>> pictures will help a lot, so I'll reserve further comment til you can
>>> upload them, thanks,
>>> What are you using as a light source? What's your ambient humidity
>>> On Apr 25, 2007, at 11:24 PM, Jacek wrote:
>>>> Hi all,
>>>> I tried my second attempt. Just a basic outline first on what I did.
>>>> Arches smooth 300gsm and Fabriano Acquarello 300gsm
>>>> 1. boiling water pre shrinked for 10mins. Dried for a day.( no more
>>>> speckles in the Arches)
>>>> 2.Gelatin 3g to 500ml, cold water for 10 mins... Heated to 43
>>>> degree Celsius.
>>>> 3.Added paper to the tray of gelatin for a minute, took excess
>>>> gelatin off by sliding the paper on the side of the tray. Dried for
>>>> the day. Stored the same Gelatin in the fridge
>>>> 4.Reheated the gelatin the next day. Recoated the paper the same
>>>> way. Dried.
>>>> Didnt add any hardner as yet, as I cant seem to get time to go buy
>>>> any! :)
>>>> 5ml 13% Pot Dich + 5ml Gum 35% + Windsor&Newton LAMP BLACK a very
>>>> SMALL smudge! (coudnt get any Ivory black as yet, will do so..)
>>>> Coated paper, fan dried for 15mins.
>>>> Added a negative with squares 2% increments made in photoshop from
>>>> white to black. Each 2% square has a number on it, which should
>>>> clearly be seen when printed.
>>>> The sheet of Arches had 3 of the same negatives on it, each exposed
>>>> 4, 6, and 8 mins. Just covered each negative when it passed the min
>>>> Developed for 5 mins face down in room temp water.
>>>> Next tray developed for 5 mins face down in room temp water.
>>>> Next tray developed for 20mins same room temp water.
>>>> On the Arches paper I got:
>>>> What I got was NO staining in highlights or midtones or the whole
>>>> paper. They looked ok though a little on the light side the tones
>>>> came up.
>>>> Can read all the incremented 2% numbers in those areas.
>>>> The shadows are another business altogether, what I got was a
>>>> massive yellow staining probably from the dichromate, plus it
>>>> looked like a real mess as I couldnt really make out the
>>>> incremental numbers from the negative. The mess seemed like too
>>>> much watercolour overpigmented, its not one colour but just smudges
>>>> of watercolour and yellow staining.
>>>> Reading Katharine suggestions, I'm thinking what I'm looking at
>>>> could be OVERexposure? or the small Smudge I used from the lamp
>>>> black is still too much pigment!?
>>>> I doubt it was caused by overcoating, as I turned each of the 3
>>>> negs upside down side by side, got the same result on each part of
>>>> the print.
>>>> Could it be my sizing, and not using a hardner? Though the
>>>> Highlights and Midtones look good?
>>>> I got kind of fed up looking at the yellow staining and used a 5%
>>>> potassium metabisulfite solution, sprayed with a hand held spray
>>>> gun. Didnt work as well, next time i'll use a tray bath.
>>>> The other Fabriano Aquarello paper I'll add more info on it later
>>>> can't recall what it looked like, but had the same sort of problems
>>>> as above.
>>>> I'll scan the prints when I get home and upload to a website.