Re: Unknown area in Gum printing?
Hi, 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. Cheers guys. Jacek On Fri Apr 27 3:04 , Katharine Thayer <kthayer@pacifier.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. >kt > > > >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. >> >> http://www.jagnight.com/Archesall3.jpg >> 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: >> http://www.jagnight.com/Fabriano812.jpg >> 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 >> smudgy. >> >> ------------------------------------ >> >> 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! :) >> Jacek >> >> >> >> On Thu Apr 26 21:11 , Katharine Thayer kthayer@pacifier.com> 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 >>> like? >>> Katharine >>> >>> >>> >>> 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 >>>> mark. >>>> >>>> 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. >>>> >>>> Cheers >>>> Jacek >>>> >>>> >>>> >> >>
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