Van Dyke Brown prints with too much flat blacks...

sanking said:

I would have to suspect that the reason for the lack of Dmax you are seeing is a negative density range that does not match the very long exposure scale of vandyke. Low Dmax would be expected if you print with negatives that are too low in contrast because the highlights print in before the shadows have received enough exposure to print deeply. I would say that this expereience is the rule rather than the exception with beginning vandyke printers because very few people start with negatives that have anything like the density range needed, whichis on the order of log 2.20 or even higher. This is much higher even that what we need when printing straight palladium, and is about the same as needed for albumen, POP and salted paper.

Click to expand...

I'm creating negatives with PDN system. Before creating the curve on Photoshop I used a Stouffer exposure guide to determine the printing time for the black point. And I can't understand how I could get a deeper black when the true black is printed without any ink on it (it's just the fog base of the transparency sheet...). I've no problem with highlights and generally with midtones, where the ink is and which print almost fine.

I've tried Arches Platine. With Cyanotypes is very good, although with Schoelleshammer I get a slightly higher dmax and deeper blacks (this paper is very fine to print with, although other papers, such as Arches, offer a more nice texture). With VDB I'm still disappointed. The true black isn't... "black" and is still even lighter (tried different exposures).

How about coating and/or drying? I double coat the paper and dry it with an hairdrier (coat the first layer, dry for <5min; coat again and dry again for 5min). But I know that if one uses too much emulsion or if the emulsion is distributed unevenly, there might be puddles on the paper which result in a sort of solarization in the final print (lighter tone). Perhaps two coats are too much with my emulsion and my brush... Or perhaps it is the drying which is not good. I'll try with single coating next time and let you know. How do you dry your coated sheets?

Thanks
Fulvio

I'm sending a test I've done yesterday.

Arches Platine (the plain side) double coated
Epson R2400 Digital negative according to PDN standards

6'30" exposure under UV lighting (BLB)

90" acid bath (actually two baths of 45" each in acidified water)
40" fixer
30" stop bath (water acidified with acetic acid)
35' washing

See all the area surrounding the color tables and the guy on the left? That's supposed to be pitch black, the negative is completely transparent on these areas and should print a lot more darker...

Today I've tried also a single coating, but doesn't seem to be better. Unless it is the developing steps, perhaps the coating&drying isn't accurate... How do you do that?

by opposite, just for comparison, this is another test with cyanotype again on Arches (this is a bit old and I've retouched the curve since then)

Fulvio said:

I'm sending a test I've done yesterday.

Arches Platine (the plain side) double coated
Epson R2400 Digital negative according to PDN standards

6'30" exposure under UV lighting (BLB)

90" acid bath (actually two baths of 45" each in acidified water)
40" fixer
30" stop bath (water acidified with acetic acid)
35' washing

See all the area surrounding the color tables and the guy on the left? That's supposed to be pitch black, the negative is completely transparent on these areas and should print a lot more darker...

Today I've tried also a single coating, but doesn't seem to be better. Unless it is the developing steps, perhaps the coating&drying isn't accurate... How do you do that?

Click to expand...

Im not an expert... but that looks alot like bad solution and/or bad coating. I had similiar results with some bad brushes.

I'm going to weigh in on this,because I've done a fair share of VDB printing-

It's called Van Dyke*Brown* for a reason-

What you might be looking for is Van Dyke *Black*,which I'm not sure exists.

Don M said:

I'm going to weigh in on this,because I've done a fair share of VDB printing-

It's called Van Dyke*Brown* for a reason-

What you might be looking for is Van Dyke *Black*,which I'm not sure exists.

Click to expand...

Nope. I've seen well executed VDB prints too and the darker tones were actually much more darker than in my prints. You can also take a look on the VDB galleries on alternativephotography.com. When I mention "black" I'm just indicating what would be the "true black" in the VDB tone scale, which of course isn't really "black" (like 0,0,0 in RGB) but it shouldn't be that light. In fact other tones in the scale - which are indeed brown and I like them - are almost acceptable. Perhaps mine or your monitor isn't calibrated well, but if you see the previously attached scanned print to appear fine, imagine it lighter and with more flat darkest tones. Or open it with photoshop and take a look at the histogram.

A friend of mine suggested that what I'm seeing are solarized puddles of emulsion which tend to fog the darkest tones and turn them into ligher ones. According to him, the problem might be in the chemicals or in the way I coat the paper. As for the chemicals, I don't know what could be wrong... I've used the same ferric ammonium citrate also for making my cyanotype preparate and works well there... Perhaps it is the coating or the drying. Today I'll try to let dry naturally the coated paper without accelerating with the hairdryer and see.

Thanks for your comments

Solarisation is different - and you'd see the darkest shadows going lighter.

It look to me as if your negatives are simply too "short", so that the shadows are underexposed. VDB takes really, really high contrast negatives, you shouldn't expect to get good results from the same negative on cyanotype and VDB.

I have no idea of the contrast range possible with your setup. I use only sheet film, and most of those are unable to build sufficient highlight density without resorting to staining developers.

Ole said:

Solarisation is different - and you'd see the darkest shadows going lighter.

Click to expand...

yes, and this is a possibility

It look to me as if your negatives are simply too "short", so that the shadows are underexposed.

Click to expand...

so... do you suggest that the transparency I'm using to print the digital negative produces too much fog base? But also with the Stouffer step wedge scale (which is film negative) doesn't change a thing. We're talking about blacks, the blacks are printed in the areas of the negative that are totally trasparent. I can't get more transparent than a glass! (In fact I've printed also strips of paper without anything on it and still it is too flat, no matter how long I expose... 5...10..15...20...25 minutes... there are no changes in the blacks from 6'30"; below that exposure time they can be lighter due to underexposure)

Fulvio

What I'm saying is that on my "good" negatives, the highlights correspond to step 19 to 20 on a 21-step Stouffer step wedge while the shadows still show good detail. I notice your negative is a good deal shorter, and only about half the steps show definition - the rest are paper white?

You should be able to expose a lot more before the shadows solarise!

Ole said:

Solarisation is different - and you'd see the darkest shadows going lighter.

It look to me as if your negatives are simply too "short", so that the shadows are underexposed. VDB takes really, really high contrast negatives, you shouldn't expect to get good results from the same negative on cyanotype and VDB.

I have no idea of the contrast range possible with your setup. I use only sheet film, and most of those are unable to build sufficient highlight density without resorting to staining developers.

Click to expand...

Ole's comment about the tonal scale of your negatives being too short is essentially the same thing I said earlier, and after looking more closely at the print out of your Stouffer step tablet I think we are right. In looking at the vandyke print of your Stouffer it appears to have no more than about 11 steps printed, which would mean that your print has an exposuure scale of about 1.65, assuming that Step One is maximum black. This is much too short for vandyke, as your ES should be on the order of 2.25 or more with the classic mix. Therefore I conclude that the most likely scenario is that 1) your Stouffer step tablet is under-exposed by more than one full stop, and 2) you have probably chosen a color for your PDN system that results in two short a DR for your negative.

Sandy

Ole said:

What I'm saying is that on my "good" negatives, the highlights correspond to step 19 to 20 on a 21-step Stouffer step wedge while the shadows still show good detail. I notice your negative is a good deal shorter, and only about half the steps show definition - the rest are paper white?

You should be able to expose a lot more before the shadows solarise!

Click to expand...

As far as I've seen I have no way to get all 21 steps printed correctly. If I expose too long, to have some color in step 20, then I have maximum black too much above step 1. On the other hand, if I want maximum black in step 1, highlights will never get enough light. If I understood PDN correctly, one needs only to find the base printing time with the Stouffer. That means, only the time required to print the maximun black tone. Once this is reached, one has to find the color which will print white with the same exposure time. The color I picked for VDB digital negatives is R=140,G=255,B=0 (but I've also reinforced the whites with a 50% multiply layer of black, with underliyng values of 125-225). Then, one has to calculate the curve that will produce all the tones between pure black and white. I did this using the table provided with PDN and the excel calculator.

Now, in the previously posted test image, the big tone scale on the left is the result of the applied curve. The original stouffer step wedge was placed above the negative on the right of the print, just under the picture of the guy - it is not part of the digital negative, it's film and therefore doens't benefit of the curve. Also, you can't see all of the 21 steps because there wasn't much room and I placed the strip incorrectly... So only steps until 3-4 are clearly visible. Steps 2 and 1 weren't printed (which makes the whole printed step wedge useless in this case) - my fault.

To Sandy - Thanks for your comments. Unfortunately I don't have a densitometer, but I'm realizing how useful it could be. How can I improve my PDN negatives?

I've noticed that with Schoellershammer paper I'm getting much better results. The reason might be that Schoellershammer paper is gelatin sized, while Arches (and other paper I tried) shouldn't. This might be the important to have good results. I could size an Arches to see if there are any changes. However, I never sized a paper... Perhaps I'll open a new thread or check older threads on the topic...

many thanks

ciao

Fulvio said:

As far as I've seen I have no way to get all 21 steps printed correctly. If I expose too long, to have some color in step 20, then I have maximum black too much above step 1. On the other hand, if I want maximum black in step 1, highlights will never get enough light. If I understood PDN correctly, one needs only to find the base printing time with the Stouffer. That means, only the time required to print the maximun black tone.
ciao

Click to expand...

Fulvio,

It might be better to forgot about PDN for a minute and just concentrate on printing a Stouffer step tablet in vandyke and looking at the results. That way all of use can have some common point of reference. I also use PDN but a direct printing of the step tablet is a more direct method of evaluating our exposure, mix and papers.

So what I would ask is that you print a step tablet with the paper you hope to use. Expose the step tablet so that there is merging of maximum black at about Step #2 or #3. Then count the number of steps from the first merging to the last step that has any density. When I do this with my vandyke mix I get between 13-15 steps, which suggests a paper exposure scale of somewhere between 1.95 - 2.25. This is very typical for vandyke using the classic mix. How many steps do you get with the papers in use?

Sandy

Thanks Sandy.

I've adjusted exposure and developing times and concentrations (added a pinch of sodium carbonate to the fixer) and now the process works pretty well.... But I still get pleasant results only with Schoellershammer paper! I have a tonal scale that meets your description (~13-14 steps with the stouffer) and now the blacks almost satisfy me (I have still to improve coating, perhaps a glass rod will do the job a lot better). The reason why I'm not satisfied with other papers including Arches Platine could be the sizing. Schoellershammer is hard gelatin sized. In fact, also Cyanotypes are a little deeper with Schoellershammer. I don't think it is the paper that makes the difference, it must be the sizing.

I'd like to size some paper to have a definitive answer. I have some cornstarch and also gelatin (it's not the edible kind). I'm not very sure about quantities of sizing to use... The books I have mention gelatin sizing, but I don't know if the gelatin I have is the same. The books also suggest cornstarch/arrowroot sizing, but don't tell much about dosages and mixing... Which quantities I should use? Is there a guide on how to size papers on the internet? (not specifically for photographic purposes, of course).

Fulvio