From: pete (temperaprint@blueyonder.co.uk)
Date: 02/09/02-01:50:49 AM Z
on 9/2/02 5:49 am, Cactus Cowboy at cactus@tritel.net wrote:
> Dear Judy:
>
> Paul Anderson may have had "bad habits", but that does not mean he created
> or caused a pigment stain problem. Most gum printers will agree that too
> much pigment in the mix will create an undesirable stain. That none of
> Anderson's contemporaries (excepting Casell in 1911) mentions staining as a
> problem shouldn't mean much to you.... After all, you did dismiss the past
> with the following quotation:
>
>> "HISTORY IS MORE OR LESS BUNK..."
>>
>> That's one of the more famous sayings of that great American Gum Printer,
>> Henry Ford
>
> Let's focus on the present, and what we've learned from personal experience.
>
> I've used 30% ammonium dichromate and 10% potassium dichromate solutions
> extensively. Using the same pigment/gum mixture, I've made identical test
> exposures with both AD 30% and PD 10% respectively. The results? AD yields
> muddier, lower contrast prints. PD will produce deeper shadows, more
> contrast, and a shorter scale. Even after adjusting exposure to negate the
> difference in emulsion speed, AD will create a very slight apparent increase
> in pigment stain as compared to using PD. But pigment/gum ratio has a far
> bigger impact on staining than sensitizer does.
>
> Judy writes:
>> I suppose some folks reading this will still demur. So under separate
>> cover I outline a few simple tests for proof. Meanwhile, I note two
>> bizarre phenomena that shed more light on the process. First, am I the
>> only one who has made a test strip with some weirdo brand of watercolor
>> that likes to stain and found that whites cleared up to step 10 or so,
>> then began a reverse scale, building tones IN PIGMENT STAIN, in nice stair
>> steps, but now in reverse, lightest at step #11, darkest at the top? At
>> first I suspected a light leak, then realized that, being so consistent,
>> it had to be the material itself. I asked the list, under some subject
>> line like "Gum Mystery," probably in early 1995. No answer.
>
> No, you're not the only one. I wasn't on this list in 1995, but I'd
> experienced this phenomenon over 10 years ago. I saw the same effect using
> Sennelier Mars Black (dry pigment) mixed 1g/20ml gum with PD 10% sensitizer.
> Sennelier Mars Black is an iron oxide pigment that's prone to heavy
> staining.
>
> You like to come off as a 'new authority', someone who's making exciting
> discoveries, Judy. I (and I suspect many others) have made the same
> observations and have had the same experiences you've had in gum printing.
> Indeed, nothing you've offered in your magazine or on this list regarding
> gum printing has been news to me. Much of what you've written I've doubted,
> due to your imprecise methodology, e.g. "Choose a tube watercolor that likes
> to stain. Mix enough of it into 10 cc of gum arabic to make a strong color."
>
> What exactly is "strong color"? How is the pigment being measured? By eye?
> By weight? By volume?
>
> You've frequently maligned the writings of Anderson, Crawford, and Scopick
> regarding the gum-pigment-ratio test. How many times do you need to beat a
> dead horse..... We all understand that sizing, type of paper used,
> sensitizer, dilutions, temperature, and exposure have an impact upon
> staining. But that does not mean the test is meaningless or without value.
> It is a quick and easy way to determine an approximate *starting point* for
> gum/pigment ratio.
>
> How many gum printers out there are using Burnt Sienna and Thalo Blue? How
> many of you use them at exactly the same pigment/gum ratio? LOL! Any
> 'doubters' should try the pigment-gum-ratio test (follow instructions given
> by Crawford or Scopick) using these two pigments. If any of you don't see
> strikingly different results, I'll eat my cowboy hat!
>
> It's apparent that you favor a casual 'mix by eye' approach Judy. Given
> that, the very notion of a measured gum/pigment ratio is meaningless to you.
> I'm not knocking your printing methods as long as they work for you and
> you're happy with the results. If you can't or won't appreciate the value
> of using a precise approach to gum printing, please don't criticize those
> who do.
>
> Best regards,
> Dave Rose
> Big Wonderful Wyoming
>
> ----- Original Message -----
> From: "Judy Seigel" <jseigel@panix.com>
> To: <alt-photo-process-l@skyway.usask.ca>
> Sent: Friday, February 08, 2002 2:54 AM
> Subject: a funny thing/ Re: Anderson again two
>
Well done Dave I think you have covered it all but I do think it is time to
put this one to rest, before it Degenerates !
Pete
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