[alt-photo] Re: salt printing - integrated density
Gordon J. Holtslander
gjh at shaw.ca
Sat Aug 25 22:02:42 GMT 2012
It may be possible to analyze the image/negative to predict the amount
of reduced silver is produced in a salt print.
I used the public domain Scientific Image Analysis Program ImageJ a
One of the measurements ImageJ will perform is the integrated density of
Integrated Density - Calculates and displays two values: "IntDen"
(the product of Area and Mean Gray Value) and "RawIntDen" (the sum of
the values of the pixels in the image or selection).
RawIntGen measures the sum of values of each pixel in an image (or
selected region of an image)
This value would be equivalent to the summing the density of each pixel
in the image used to produce the print.
Since the density of each "pixel" in a negative would determine how much
metallic silver is produced in a salt print, the RawIntGen value would
be strongly correlated with the total amount of reduced silver in a salt
Could this value be used to predict the total amount of reduced silver
in a salt print
ImageJ is support by the National Institutes of Health
ImageJ is available for Windows, Mac, linux - anything that will run Java
More info on ImageJ http://rsbweb.nih.gov/ij/index.html
Users guide http://rsbweb.nih.gov/ij/docs/user-guide.pdf
On 8/24/2012 6:23 PM, Christina Anderson wrote:
> Ohmagosh. I see. That is VERY interesting and makes total sense, that the amount of reduced silver in the image depending on the shadows or highlights of that particular image, would influence color. Very neat. Not read that in the literature.
>> Not quite. The affect on color is relative to how light or
>> dark the image is... how much silver is held in the paper to form the
>> image... that's the killer for me. No matter how exact I measure the
>> chemistry, the amount of silver that forms each image will affect the
>> final color. I'm conjuring up a plan to use a histogram to guide my
>> tweaking... haven't gotten down to designing the information transfer to
>> a volume or time variable yet and it might be a bogus idea... too soon
>> to tell.
>> I'm measuring with a 10ml syringe.... exactly 4ml per 12x15
>> sheet. I might be off a drop or so, but not much. I could try measuring
>> drops as a means to reduce another variable I suppose.
>> I know the
>> table you're referring too with the speedier salts listed against their
>> contrast. In my experience the isn't much difference in contrast, only
>> speed and final color.
>> One last note, the final color can't be judged
>> before the print is totally dry. That tends to slow down these tests.
>> Humidity is pretty constant since I have AC in my darkroom, but since
>> it's MI... it's always high.. 55-65%
>> On 2012-08-23 12:28,
>> Christina Anderson wrote:
>>> Can I quote you :)? I am
>> thrilled to find someone really doing salt on this list, separate from
>> albumen anyway...
>>> Do you find salt a longer tonal range than
>>> What is your choice of fixing bath and time?
>>> So the
>> amount of silver nitrate influences color...you would have to be,
>> therefore, exact with your drop-to-sq.-inch count to get similar color,
>>> One thing I am puzzling with is Young's use of the word
>> "contrast." If a certain solution is faster in exposure, she then
>> equates it with lower contrast. Now, I could be the one confused but I
>> have always understood contrast to be separate from exposure. Once
>> maximum black and maximum white are achieved, the number of steps
>> between the two is either fewer (more contrasty) or greater (less
>> contrasty) but if comparing faster and slower solutions this gives a
>> false read.
>>> That would be like, in the B&W darkroom, exposing a
>> grade 0 paper and a grade 5 paper the same time and comparing the
>> papers' contrast.
>>> I would first get the standard printing time
>> (SPT) and then compare the number of steps. But I could totally have it
>> wrong all these years. PLEASE correct me??
>>> I have the PDF, and just
>> ordered the book, but thanks for the offer. I wanted to see the step
>> wedges in print.
>>> I do like her clear method of writing and
>>> An off-lister suggested Ware's article on salt, too.
>> OH, one other thing. I was able to see Panera and Hajicek's giant salt
>> print photograms done in the sunlight at F295 a few years back. Now THEY
>> were stunning. And of course Dan Estabrook's work is a favorite of mine.
>> Jesseca Ferguson as well.
>>> Christina Z. Anderson
>>> On Aug 23, 2012, at 12:09 PM, Darryl Baird
>>>> Chris, I spent a good portion of this year working on
>> getting salt printing "down" and I've discovered there isn't a single
>> formula published that works completely as "advertised" in any of the
>> sources you've just cited. Young's work is, by far, the most complete,
>> yet there are gaps or things a little glossed over. I revised Young's
>> formula (using Potassium Chloride) with a couple of additives in the
>> sizing, and a minor modification in the hypo stage. I was happy...
>> notice the past tense. Young published her research as a dissertation
>> first, then revised it into the pdf "manual." I have both if you'd like
>> a copy of the former. One of the latest finds (for me) is a statement by
>> Reilly about the color also being determined by the amount of silver
>> used (retained in the paper) in making any image. It made perfect sense
>> that the final amount of silver within the image being toned would have
>> an affect on the final color. This one little "detail" sent me over the
>> top considering I want EVERY print I produce in a portfolio to match in
>> color. So, my next challenge is to manage a method to estimate the
>> amount of total silver present and adjust either my toning time or
>> volume for each image. PITA I'd already resorted to a single-shot
>> solution for each step, never reusing chemistry in order to narrow or
>> eliminate the color variables from each.
>>>>> From Reilly, Chapter
>>>> Toning "Among the factors which influence the outcome of the
>> toning operation are the pH of the binder (gelatin, arrowroot, albumen,
>> etc.) materials used, the pH of the silver solution, **the amount of
>> silver deposited to form the image,** the thoroughness of the initial
>> wash in processing, the pH of the toning solution, the presence of other
>> substances in the toning solution, the strength of the gold solution,
>> its temperature, its age, and the time of immersion of the print." Steve
>> Achell has some helpful advice in this document... it was helpful in
>> some of my formula changes.
>>  and
>> I'm also going to start a new printing test using fumed silica.
>> Darryl On 2012-08-23 09:50, Christina Anderson wrote:
>> All, I noticed last night when googling it that it is available on
>> Amazon here and also on the alternativephotography.com website
>>>>> lt-Print-Manual-Ellie-Young/dp/144528328XFor some reason,
>> how long I have had it, I have a PDF of it from the web, so at one point
>> it was free. In any case, I want to give credit to her for her research
>> and did buy the book (I can't stand reading PDFs). It seems between
>> Reilly, James' chapter on salt in his book, and Young's book there isn't
>> too much other current literature on the process, unless it is just
>> lumped under albumen which is quite popular. OH and Ed Buffaloe's
>> article on unblinkingeye.com which BTW includes a CASEIN sizing for the
>> salt print I am dying to experiment with, because it would be matte like
>> casein is, and like Reilly talks about
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Gordon J. Holtslander
gjh at shaw.ca
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