Loris,sorry that I just realized I should make selection according to the way you made it in your attachment.
10-drop strip: step 1,2,3,4,5 turn to black simultaneously.But the K value of step 6(85%) is the same as step 1,2,3,4,5.So the Dmax is supposed to be step 6?
8-drop strip: step 1,2 turn to black in order.But the K value of both is the same(87%).So the Dmax is supposed to be step 2?
It's so puzzling.Why are they so different? The drops are for an coated area of 4x5 inches and both of the strips are from the same piece of paper.
Sudek, hi. Indeed with the 8d target, steps turn black in sequence. I didn't check the 10d target.
1. When coating volume per area changes, a very important process parameter changes. That's the reason for wildly differing results. *Use at least 0.25ml per 10 sq. in / 0.0039ml per sq. cm of coating solution*. Some papers will need a little less, some a little more, but those figures makes a very good starting point.
2. I see you still use a small area for coating, and the step tablet is very close to edges of the coating area. This is not a good practice; the edges often behave differently because coating isn't absolutely and perfectly even on the edges - definitely not a good place in a context of calibration! *Coat a larger area and keep the step step tablets at least 1-1.5" away from edges*.
3. OTOH, it's very hard to judge and mark the correct place with the standard Stouffer step tablets, because there aren't any helper marks on the negative, also the steps aren't equally sized. *I'd strongly suggest that you use Mark Nelson's tablets*. They're very nicely designed, you can discern each step very clearly because they're marked on the negative. And the numbers are readable in all steps. See the page, you'll understand why using these is considerably more productive...
4. Maybe it's time to consider a workshop; seeing a master at work will improve your grasp of the workflow immensely.
Loris,I did order a Mark Nelson's 31 step tablet last year according to your previous suggestion.I didn't receive it after waiting for more than one month.Mark Nelson said he didn't know what was going on but he was very nice and gave me full refund.And he suggested me to look for other step tablets like Stouffer.That's why I bought the Stouffer step tablets later on.
And believe me that I have no intention of insisting on coating small areas.I remember you said I should coat an area at least same as the final size print.I coated for 4X5 because that would be one of my final sizes.I would tear it into two parts(2X5 each) and placed the tablet in the middle of each part.
I'll redo it according to your suggestions of coating volume and sizes tonight.
Thanks so much for your immense patience.And sorry for all the trouble.I'm really very grateful for all your kindness and warm-hearted help:)
I really don't like Stouffer's tablets. You can't discern the lower steps easily, and I just realized that in your test the steps aren't equally sized. Nevertheless use a larger area for tests, wouldn't hurt (vice versa is prone to troubles) - you need a clean and even coating to place the step tablet on. And try to be extremely consistent with tests.
Good luck & regards,
One more note: if you're concerned about washing precious metal down the drain, first try with traditional cyanotype. It's actually harder to get good results with traditional cyanotype (very good tool for practice / learning, and it subdues the practitioner - alot!) but it's cheap and pt/pd will be (much much) easier later. (In terms of being able to get equally good results - within limitations of each process...)
Loris,thanks much for the kind suggestions.But I think I shouldn't give up so easily after "torturing" you for such a long time.:)
I would post the good news when I have one.
Thanks again for all the warm-hearted help:)
I have also been following this thread and have found it very useful. I would like to commend Loris for his community spirit.
Sorry for the late report. I had surgery and just got back the experiment recently.
And good news finally. The exposure time is 7 mins 30 sec.
I know I could never have made it without your encouragement along and all your warm-hearted help.
Thank you so much!!!
Hope you're well now.
Happy to hear about your good results, I'm glad if I had provided the tiniest bit of help to you.
So, what's your verdict about your previous problems? How you managed to solve it in the end?
I'm fine now,thanks!
No doubt your help to me is enormous.I'll always be grateful for that.
It was solved by chance.Usually I would coat paper that has been exposed to air in the room for 24 hours(humidity is about 70%). Someday I was busy and didn't coat it till three days later. And the result was different. It seemed the problem was the humidity in the paper. Does it sound queer?