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Light Farm silver gelatin web tutorials

Lastly, one other (OT) thing I will post here since this thread is getting some traffic.

CHEMSAVERS on eBay has listed at this moment 250mg of 1,1′-Diethyl-4,4′-carbocyanine Iodide, otherwise known as kryptocyanine for $27 plus shipping. This is one of the sensitizing dyes on PE's list and, IIRC, is a sensitizer for the red and near infrared. Go on eBay and search on "carbocyanine."

This is why I say to watch eBay. Maybe it is available through their website as well.

I'm not going after panchromatic emulsions at this time so I'm not picking it up but thought someone else in the forum might be interested.

Now, back to the topic...

-- Jason
 
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I love the scratch cake v. box cake analogy. Spot on.

Need to clarify an important point though. It's a frustrating (to me) source of confusion.

"Silver gelatin emulsions" is a big universe, covering not just space (i.e. products available commercially today), but also time (i.e. products available at different times since 1880.) That part is pretty general knowledge. What can be confusing are the very real differences between paper emulsions (almost all neutral, unwashed, unsensitized -- don't worry about what those terms mean now: all will be revealed! -- just think old-timey) and negative materials emulsions -- which range from basic dry plate to the most sophisticated modern film.

A basic paper emulsion (minimal tools and materials), well-coated, is virtually indistinguishable from commercial. I often compare a handmade recipe to Lodima paper and if I coat on glossy, commercial baryta, I have to make sure I take careful notes as I process or I won't able to tell which is which after the prints are dry.

It's possible to leave "hand of the maker" tells on handmade paper, but that is a creative decision, not a technical default.
 
Thanks! Scott and Jason for the info about Chemsavers. They're a great resource that has managed to escape my notice. No longer. Bookmarked!
 
Is Bostick and Sullivan on your list? I have found decent prices on some things there, such as gold chloride.
 
Good to see things moving along! All thumbs up!
 
Dont forget that the Formulary has a number of unlisted chemicals for emulsion making such as PMT (Phenyl Mercapto Tetrazole) and TAI (Tetra Aza Indene). These are excellent antifoggants and stbilzers that are used in a number of emulsions. With TAI (supplied as a powder or in solution) you can make your emulsion keep for a long time with no change in properties.

PE
 
I've got questions about a couple items that need to be purchased.

I've got a 1/4" 11x14" piece of glass that I plan to use for contact prints in my darkroom. I haven't used it yet but I thought I could either lay paper, negs and glass on the baseboard, or get some thin foam to lay on top of the baseboard first. Will this work for the project? Or do I need to purchase the contact frame that was suggested?

Also we need a "reliable" scale that measures as low as 0.01 g. First could I get some recommendations as to which ones are "reliable?" Also what's the top end the scale should be able to measure? Some are 20g, some 500g, etc.

Would either of these fit the bill?

http://www.amazon.com/US-Balance-Digital-Scales-Silver/dp/B00123AVTO
http://www.sciencecompany.com/Parts-Counting-Compact-Scale-2000g-x-01g-P16791.aspx

Thanks,
 
Kenton,

The one from Amazon looks like a great scale.

The two scales are a perfect example of the trade-off between upper and lower end precision -- at least for any scales I can afford. The rule of thumb I was taught is that you want a decimal point of measurement beyond what you expect to weigh. i.e.: If a recipe calls for 5.5 g of doodlebugs you'll want a scale that measures to 5.50 grams. I have two scales that have almost the same ranges as the two you have here. I almost never pull out the 0.1 scale. I just don't have the room for two scales out and the work-around isn't a big deal. If I need 150 ml (grams) of water, I weigh out the water in a couple of divisions.

Important, though: You'll want a calibration weight, or even better, a set of them. The instructions for calibrating the scale will be included with your model. It's very easy, but very important.

Re: contact printing under glass. It can be done. It will be fine in the beginning as you're learning and deciding if all this is something you really love doing. But, in the long run, especially with handcoated paper that isn't dead flat when it dries, the tight contact afforded by a good spring-back frame can't be beat.

btw: excellent questions!
 
anikin said:
Cool! I'll get some. Which one is better? Or should I get/use both?
Click to expand...

They each have slightly different uses so I would get both.

If you are in Rochester for any reason, I can give you a tiny starter amount for your lab. Otherwise, the Formulary is your best bet. Sherry knows where the bottles are kept.

PE
 
For contact printing, I use a metal framed heavy glass printer that I bought locally at a photo store. It is so heavy that no wrinkled or curled paper has defeated it!

Denise is right thou;gh. You want something heavy to insure flatness.

PE
 
When looking at the specs for weigh scales, note that accuracy and resolution are not the same thing!
 
Hi Ian,

Nice to see you here again. I hope this means you've cleared your work load enough to get back to making emulsions!
d

p.s. In case anyone has missed it, emulsion101 is more than Ian's website, it is a silver gelatin emulsion forum he established.
 

Hi Denise,

Yes, I have chosen to forgo chasing an income for a bit, instead concentrating upon converting my earnings into silver halides ( a remarkably quick process!)
Cooked up some bromide last weekend, hoping to sulfur it and coat film this weekend.
 

Thank you. I will definitely tune in. And Happy Holy Days to you, too!
 
Excellent! With the Season almost behind us, I'm really looking forward to this.
 
Looking forward to this! Will be a help to a lot of people. Are you going to cover Silver Gelatin Paper or just plates?
 
Hi hermit,

Glad you're interested! I recognize you as a collodion guy. I hope you find dry plate enough easier, safer, and more flexible that you'll join the gelatin crew. Beauty, of course, is in the eye of the beholder, and as beautiful as a number of processes are, I don't think anything compares to silver in gelatin.

The tutorials will cover papers and negatives (both dry plate and film). I have imagined that silver gelatin is as much a part of the public school system as reading, writing, and arithmetic. We've all been through pre-school and kindergarten where we've looked at pictures and are aware of the general breadth of the subject.

The tutorials start in "1st grade" and will spiral up and through increasingly complex recipes and techniques. I'm going to try to hit a speed that everyone participating real time will have plenty of time to keep up. We'll see how all this goes as it gets more complex. I have high hopes it's going to be great. In a year or so, when everyone "graduates high school", and I know better how to do this thing from the web, I hope we can go on to bi-packs, tri-packs, near-pano film, and an autochrome-type film. Fingers crossed and face forward into the wind!

d
 
Panchromatic emulsion?

Denise,

In your most recent posting on your silver gelatin tutorial, you mention "near-pano film, and an autochrome-type film." By this, I assume that you mean some sort of panchromatic emulsion? PhotoEngineer (if you are reading this), will you deal with panchromatic emulsions in your March workshop at the GEH?

Thanks,
Charlie Palmer
 
Charles;

Making a red sensitive emulsion and then blending with a green emulsion and a blue emulsion is a good way to do it. Make a blue under amber or red safelight. Make a green under red safelight. Make a red under green safelight. Then you blend all 3 1:1:1.

BUT, with a panchromatic sensitizer and one emulsion, you essentially have to use IR goggles to do any useful work. This is pretty tough and can be expensive. BTDT.

In the GEH course, we may discuss it, (and the above is part of that) but we do not intend, at this time, to go further than discussion and perhaps an ortho emulsion. Besides, pan dyes are not easy to get and are very very expensive.

BTW, his is not covered in the book. It is a possible topic for V2 of that type of work. Hermit above may find my book interesting if he is interested in silver gelatin. I am interested to know if there should be a V2.

PE
 
Charles,

Yes to near-panchromatic. "Pano" was a typo (Actually, a brain hiccup. For the longest time when I was a teenager learning photography, I thought it was panochromatic film. That still slips out, just like my Minnesota accent, at the oddest times -- and I haven't lived in Minnesota since about the time I was learning photography. )

As Ron says, the chemistry for (true) pan film is expensive. And IR goggles are just a bridge too far for this girl. In truth, I don't personally see the need for true panchromatic film. Ilford and others make the stuff brilliantly. I want to build materials that can't be bought, and the ones that catch my fancy (like tri-packs and autochrome, and heaven help me, 16mm movie film) can be approximated with near-pan film. I have the basic recipe almost to where I want it. Still has a higher base fog than I like, and reversal is hit-and-miss. That recipe and its children will be at the front of my research schedule this coming year, sharing time with the tutorials.

d
 
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