Is food grade chemistry OK for use for photography?

Photo Engineer · Apr 27, 2009

Well, for my $0.02, 10% is no boo boo!

PE

Kirk Keyes · Apr 27, 2009

I like to look at it as 1000% off.

gainer · Apr 27, 2009

Kirk, you ought to loosen up and do something dangerous, or at least unorthodox, once in a while. Theoretical conjectures are supposed to lead to new knowledge, but only after experimental verification or rejection. I am trying to figure a way of showing in this forum the difference due to using 10 times the "legal" amount of borax in D-76. It ain't what you think. Meantime, I used my last Metol and must wait til my order comes to repeat my test.

Photo Engineer · Apr 27, 2009

Patrick;

The test should include speed, grain, contrast and sharpness comparisons of all experiments vs the reference to be a valid test. Otherwise, the evaluation is subjective.

PE

Kirk Keyes · Apr 27, 2009

Well, why not start by making a 2 g/L borax solution and a 20 g/L borax solution then measuring the pH? It should be a bit above 9. And yes, a 0.005M solution of borax will not actually have a much higher pH than a 0.05 molar solution. But it will be higher, and should more activity than one with a lower pH.

Photo Engineer · Apr 27, 2009

Don't forget that the borax solutions you mention Kirk will differ in buffer capacity by a factor of 10 even though the pH values may be nearly identical. This will affect dmax and contrast among other things. Of course, if you are using alkalinity = buffer capacity and not just pH, then I agree.

PE

Kirk Keyes · Apr 27, 2009

Photo Engineer said:
Of course, if you are using alkalinity = buffer capacity and not just pH, then I agree.
PE

I modified my post a bit as you were typing - but then we certainly agree as to the definition of alkalinity being related to buffering capacity.

Ray Rogers · Apr 27, 2009

Photo Engineer said:
This will affect dmax and contrast among other things.

PE

In a fresh solution, or only after some exhaustion?

Photo Engineer · Apr 27, 2009

Ray;

Depends on the buffer capacity and film. Dmax development with high silver will reduce the pH enough to curtail development in some cases. I have measured a drop of ph 10.0 to 4.5 in the dmax of paper with a carbonate buffer and with a borax buffer, all things being equal molar / buffer capacity. But, it varies.

PE

gainer · Apr 27, 2009

Photo Engineer said:
Patrick;

The test should include speed, grain, contrast and sharpness comparisons of all experiments vs the reference to be a valid test. Otherwise, the evaluation is subjective.

PE

My initial procedure these days involves picking a scene with a wide brightness range, bracketting + and - 1/2 stop, and shooting 36 exposures in a short enough time that lighting did not change. A strip long enough to have 5 exposures will have at least the exposure range. Contact prints side by side will show visually if there is significant density and contrast difference between two develpers. I do have the facility to measure projection density at a very small point for more critical measurement of differences.

I also have an old rangefinder back with a projection density wedge taped in place in the film plane with which I can shoot a roll of film all at the same exposure with shutter speed short enough to avoid reciprocity complications. The problem with old focal plane shutters is that the effective shutter speed may vary from one end of the frame to the other. There are adjustments, but for the person without proper equipment they are a matter of trial and error. It is nevertheless a pretty good tool for comparing films, developers and such, where absolute accuracy is not esential.

When I get my shipment of Metol and hydroquinone I will camp in the darkroom with a supply of coffee and oatmeal cookies and see what I can come out with.

I did find a jug of D-76 that I made some time ago and was able to make two strips, one as-is and the other with 4 grams of borax added to 250 ml, both for developed for 8 minutes at 68 F. I am heading to the darkroom to see if I can get some meaningful evidence one way or the other.

Ray Rogers · Apr 28, 2009

Photo Engineer said:
Ray;

Depends on the buffer capacity and film. Dmax development with high silver will reduce the pH enough to curtail development in some cases. I have measured a drop of ph 10.0 to 4.5 in the dmax of paper with a carbonate buffer and with a borax buffer, all things being equal molar / buffer capacity. But, it varies.

PE

I still have that migraine; I have injested a mantaince quantity of acetylsalicylic acid,
(ASA for short) so hopefully I will be able to get through this question!

I am not sure I follow you.

By D -max development, are you implying something other than regular negative (film) development?

Do you mean the development environment in the area that constitutes D-Max? For example, are you saying you measured the pH of say, the different steps of a step wedge print, and found the fresh developer pH to decrease from 10 to 4.5 across D-min to D-max?

or that you measured the pH of a developer used to develope a paper to D-max everywhere and that the pH had dropped to 4.5?

When you said "enough to curtail development in some cases" did you mean
concominate development or subsequent? That is, for the next sheet?
If you meant concomitant development, for the same sheet, that may not be an issue once desired density has been reached.

If the above step wedge density/pH interpretation is correct, I would assume the pH in the high lights or D-Min to still be quite high... Developer pH overall might not be 4.5.

Assumng the D-Max pH is 4.5... If we are talking one shot developers or minimum capacity developers, if sufficient D-max is obtained, final developer pH may not be so critical.

Thanks,

Ray

Photo Engineer · Apr 28, 2009

Ray;

Development consumes alkali! If there is not enough alkali, development stops short of its intended state. Development is greatest in Dmax regions and therefore both alkali and developing agent can be consumed. Therefore, it is theoretically possible to get a somewhat bell shaped characteristic curve through the lack of development. This would mean that the Dmax could theoretically be lower than or equal to the mid tones.

Now, that is an extreme just to illustrate the case I am describing.

Generally, one can see a shortening of the linear portion of the characteristic curve and a long flat low dmax. This is not good. It can take place in both negative and reversal processes and in both B&W and color developers.

PE

gainer · May 12, 2009

I have Metol and hydroquinone now and have completed some comparative tests. There will be three developers: D-76, D-76 with 10 times the proper borax, and D-76 with 20 grams borax and 20 grams boric acid. Each will be illustrated by a scan of a print on VC paper with high enough resolution to see the chiarocsuro as well as a high resulution scan of a small portion of the same print to show grain and resolurion. I don't know if it would be better sent as an article, due to its length. Any opinion would be appreciated.

Kirk Keyes · May 12, 2009

I think an article would better reflect all the work and effort you are putting into this. Posts can be pretty limiting.

gainer · May 13, 2009

Right now my problem is this: I have written my document, including photos, in Word Perfect and saved it in Rich Text Format. I can call it back up in Word perfect with no problem, but when I try to resurrect it with MS Word, the photos are all distorted, and not in a logical way. Some are vertically compressed, others seem about in the right proportions but in the wrong place, etc. I will give it a few more tries, then send what I have in hopes that someone can sort it out for me.

MattKing · May 13, 2009

Mr. Gainer:

I work almost exclusively in WordPerfect - if you'd like to send it to me I'll try to sort it out for you.

Matt

srs5694 · May 13, 2009

gainer said:
Right now my problem is this: I have written my document, including photos, in Word Perfect and saved it in Rich Text Format. I can call it back up in Word perfect with no problem, but when I try to resurrect it with MS Word, the photos are all distorted, and not in a logical way. Some are vertically compressed, others seem about in the right proportions but in the wrong place, etc. I will give it a few more tries, then send what I have in hopes that someone can sort it out for me.

I'm not sure where you're sending it or for what purpose. If you want to submit something for publication, it's almost always best to send the photos (or other illustrations) as individual files instead of (or in addition to) embedding them in a word processing document. I've written quite a few books and magazine articles in the computer field, and publishers always want photos and graphics as separate files. Maybe it's different outside of the computer field, but I doubt it.

If you want to "publish" it on the Web or otherwise distribute it electronically, look for a "save to HTML" option, or perhaps "save to PDF" if you think PDF would do better. Those are both standard formats that'll handle graphics more consistently than RTF. (Using HTML will result in multiple files, though. This is fine if you're putting it up on your own Web site, but less fine for other types of distribution.) If you can't find such an option in your version of WordPerfect, I'd be happy to help out, although I can't promise perfect results. I know I can create both document types from WordPerfect documents, but I don't know precisely how my version of WordPerfect would handle your document.

gainer · May 13, 2009

MattKing said:
Mr. Gainer:

I work almost exclusively in WordPerfect - if you'd like to send it to me I'll try to sort it out for you.

Matt

Thanks for the offer. I think I got it posted to Articles as "Borax Project". I separated the photos from the text, which was easy to submit, and sent the photos as attachments.

walter23 · May 13, 2009

gainer said:
Why should Food grade not be at least as pure as Technical?

For technical applications you need high purity. For food you need non-toxicity, but not necessarily high purity. If your Vitamin C had 10% sucrose in it (just an arbitrary example) it would still be perfectly fine to consume. However that excess 10% impurity might make it unreliable for some technical applications.

gainer · May 13, 2009

walter23 said:
For technical applications you need high purity. For food you need non-toxicity, but not necessarily high purity. If your Vitamin C had 10% sucrose in it (just an arbitrary example) it would still be perfectly fine to consume. However that excess 10% impurity might make it unreliable for some technical applications.

You should go back to my first article in "Darkroom and Creative Camera Techniques" to see what I said about ascorbic acid and vitamin C. I have used sucrose in the first bath of 2-bath developers as a means of allowing more to cling to the emulsion. I don't make recommendations for anything I have not myself used.

fschifano · May 13, 2009

Pat,

Try using "OpenOffice" to convert your WordPerfect document to either an open source or MS Word document. The entire suite of applications is free from Sun Microsystems and is compatible with MS Office files. I'm not sure if it will handle WordPerfect documents, but it handles everything else. It will even convert any document it can read into a PDF file for distribution. It has worked for me on several occasions, though I have not tested it with WordPerfect. Find it here.

Kirk Keyes · May 13, 2009

Pat - I can make a pdf out of a word doc for you if you like. Just email it to me and I'll send it back to you.

Photo Engineer · May 13, 2009

walter23 said:
For technical applications you need high purity. For food you need non-toxicity, but not necessarily high purity. If your Vitamin C had 10% sucrose in it (just an arbitrary example) it would still be perfectly fine to consume. However that excess 10% impurity might make it unreliable for some technical applications.

Vitamin C tablets sometimes contain starch. This is far more harmful to film than sucrose. The starch particles can become embedded in the emulsion, much to the dismay of the user.

Patrick will continue to defend his position but it is one like the speeder who can get away with speeding "almost all of the time". The use of substandard chemistry can work quite a number of times and then one day you have that priceless single shot that is ruined by starch in your vitamin C tablets.

Sometimes you get a speeding ticket.

PE

Kirk Keyes · May 13, 2009

Photo Engineer said:
Sometimes you get a speeding ticket.

I like that analogy!

gainer · May 13, 2009

I know I'm getting older every day, but when did I recommend the use of vitamin C tablets for developing anything but a trial? I did it once, but not again, and that was a long time ago, at least in dog years. Currently, it seems the shoe is on the other oot with regard to borax. I contend that there is nothing about the purest grade of sodium tetraborate that allows weighing a it to the milligram and being sure that you got that many milligrams of sodium tetraborate decahydrate, simply because there are both pentahydrate and decahydrate forms, and the humidity of the atmosphere each time you open the container can cause the ratio of the two to change. The requirement for photo grade borax specifies an assay between 101% and 105%. That means that there is enough uncertainty in what you get when you buy Photo grade borax that there is not much use in weighing it to the milligram, and that is true even if there is nothing in your container of analytical grade but sodium tetraborate and H2O of hydration.

Is food grade chemistry OK for use for photography?

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