Photographers' Formulary

[Vaughn]

"I don't want to hijack this thread but I HAVE to know the difference between the real world and the actual world..."

Simply...there is none...just as there is no difference between one's 'real' world and one's 'theoreticall' world.

Instead, you demonstrated that there is a lot of slop available in processing photographic material.

 

[Donald Qualls]

you demonstrated that there is a lot of slop available in processing photographic material.

And that depends on how stringently you're examining your results.

I have never done sensitometry, but I understand how it works (and I'm gathering the tools to start). I'm pretty confident that someone who routinely exposed and processes test strips, and then measures the results against an established (by previous testing) curve will be able to spot a 3% variation in either developer strength or component mixture. In many cases (say, with Xtol, but more generally with most phenidone-based developers) a component of crucial importance represents much less than 3% of the total solids to be dissolved. Use a developer that comes in two or three bags, and you add another variable.

If consistency is the bane of your existence, you may as well "pinch and throw" starting from individual chemicals. I'd bet I could make Caffenol that way and get images -- but if I want all my films to be developed the same, so they print the same and I can tell if I'm over- or (less likely) under-rating film speed, I need to avoid a condition that could halve the quantity of one of the developing agents, significantly change the pH of the solution, or otherwise make a change that in fact makes a difference (or that I don't know won't make a difference).

 

[Vaughn]

Totally agree -- which is why I mentioned to David that if he approaches us with question/problems with his process, we now know to factor in his slop when we answer. If one does not shake up the orange juice, one has difficulty complaining about how weak it tastes at first and how strong it is at the end.

 

[JPD]

Whatever you do, don't ask them if any of their chemicals are "food grade". I did that once and got a deservedly angry reply!

 

[Donald Qualls]

Sure, but just trying buying sodium ascorbate or ascorbic acid that is not intended as a supplement for human consumption!

 

[JPD]

Sure, but just trying buying sodium ascorbate or ascorbic acid that is not intended as a supplement for human consumption!

It could be Technical grade or Photo grade (but I doubt that one for ascorbates and Ascorbic acid), and then it may not be suitable for human consumption. It's understandable that they don't want people to risk their health by using the chemicals for other purposes than they are intended for.

 

[Sirius Glass]

Of course, if you do it the David Lyga way, you don't need a scale, just a small, calibrated cylinder. - David Lyga

For measuring chemicals, I learned in chemistry labs and biochemistry labs, that a small scale is necessary for proper weight [mass]. They are available and inexpensive on the internet.

 

[VinceInMT]

And in Montana, if any of the remodeling involves building exteriors, suitable summer weather itself is finite, and work has to get done promptly.

Don't be so sure about that. Here in Montana exterior construction takes place nearly all year long.

 

[VinceInMT]

I believe that PF is on the Black Foot Reservation, business are closed.

They are in the Swan Valley, Northeast of Missoula about 75 miles. The Blackfoot Reservation is a ways NE of that.

 

[JPD]

For measuring chemicals, I learned in chemistry labs and biochemistry labs, that a small scale is necessary for proper weight [mass]. They are available and inexpensive on the internet.

Yes, and even if you know the volume of a certain weight of a powder from one chemical supplier it might be different if you buy it from another supplier if the size of the powder grains are different.

I have a good Acculab scale for measuring chemicals. But sometimes I actually remove scales by using chemicals, but that's from the toilet.

 

[DonW]

I heard they are back in business.

 

[David Lyga]

If measuring powder by volume is good enough for Steve Anchell (Darkroom Cookbook), I guess it would be good enough for David Lyga. Indeed, I use more precise measurement apparatus than mere spoons. - David Lyga

The Photographers' Formulary website is up.

 

[DREW WILEY]

That's nice to know. I'll be needing some more supplies from Formulary in the next couple of months.