Can't get deep black

[dwross]

From "A Joe":

Can't get deep black
I'm using kevin klein's bromide emulsion (TLF) but I can't get deep blacks out of it. It's not exposure (tried a sample completely fogged), it's not developer (both my own D19 and kodak dektol with the same results) and it's not thickness, I coat with brush or puddle pusher and got good blacks with other emulsions.
Dilution is ok, gelatin content is ok (I made this formula more than 10 times), sensitivity is between 1-3 depending on the batch. No fog.

should I add iodide?
thoughts?

 

[dwross]

Every emulsion has its own personality. Kevin's emulsion could be described as "quiet", "soft", or "delicate." No matter the density of the blacks on the plate, it will make a lovely print -- either scanned for electronic viewing or digital printing, or enlarged on the right paper. If you want an inherently more vigorous emulsion, you might try the "Plain Silver KBr" emulsion on TLF. It comes with complete making instructions in the tutorial section.

That said, there is a way to make Kevin's emulsion stronger. You need to remove more of the washing water than happens simply by draining the noodles. As the emulsion is written, it is 8% gelatin. If you assume that you add up to half again the water during washing, the emulsion concentration goes down to as low as 5%.

Solution: When you have drained the noodles as described by Kevin (and assuming they are in a cotton bag or otherwise contained), roll the bag of noodles in a clean terry bath towel. Twist and squeeze both ends just as though you were trying to wring out the water from a wet towel. Unroll the towel and move the bag to a dry section and do this again. You will have gotten out most of the excess water and this should improve the density of your plates. Good luck and fun!

 

[A Joe]

I've compensated gelatine to be around 9% after washing because of the excess water. I'll try both.

And I can post now!

 

[dwross]

Yay!

It's great to see someone who thinks through the logic of an emulsion! Adding gelatin is an excellent way to bring up coating viscosity. However, you are probably still left with less silver halide per area coated than if you remove some of the washing water. I love that you are trying both. I'd really love to see posts of your results!

Another option to try is to heat the washed noodles before coating, rather than simply melting them. Bring the heat (in a waterbath is best) up to 40-45C. Start with 15 minutes, then bring the temp down to coating temp. You can increase both time and/or temperature (no higher than 55-60C, though) in stepped increments and see if you can get closer to the results you are looking for. At some point, you'll start to see a little fog. That's when you know you've taken things as far as they'll go. You can then drop down to the adjustment level one step back, and call that your standardized, personalized recipe.

 

[dwross]

Did my suggestions about adding a heat step make sense? I get worried when there isn't a response. I have to assume that when a person takes the time and effort to join something and post a question, there is an interest in dialogue on the issues. Without feedback, I don't know if I've slipped into blather and jargon. Don't want either, and I certainly don't want to waste anyone's time (and that includes my own, of course ).

 

[A Joe]

My current recipe calls for 20 mins 55 deg. I tried at about an hour but I got fog. I can try something in the middle anyway, I'll try it in my next batch.
With 20 mins I got clear whites and about 3asa in daylight, but I still can't get rich blacks if I coat on paper. On plates it's a whole another story, I shot a really nice picture of my cat and enlarged the plate in RA4 paper, creating virtual color with the enlarger settings (he is plain white as you can see in my avatar).
Btw I've been using fabriano artistico and other +300g cotton (not 100% cotton, just a percentage) that I can't recall the name now, it's really thick. I love when the paper has a lot of texture and brush paint the emulsion. If you play big paper sizes like 10 x 20 it's gorgeus (the strokes are less apparent)
I managed to do nice brushes at 35-40 deg, but you'll spend lots of emulsion on the 300g paper. Anyway, not a big deal if you cook your own, it's cheap.
I also tried to selenium tone it but didn't improved the "blackness" of the blacks.

My recipe has only bromide that's why I've asked if it makes sense to modify it and include some percentage of iodide to help contrast/blacks.
I'm a thousand miles away from my lab and I'll get back there in a couple of days so now I can only speculate on the results.

Have you ever used coarse grained paper? do you like it? it's more forgiving than the baryta when it comes to coating.

A.J.

 

[dwross]

Aha! OK, I think I see the problem. Kevin's emulsion is intended solely as a plate emulsion. A washed bromide emulsion does not deliver rich blacks on paper. Indeed, soft blacks and a very full density range are its intended purpose in life. Historically, "bromide" paper was the segue from the P.O.P. printing processes that proceeded silver gelatin papers. The long range of the paper accommodated the negatives that photographers also used for albumen, carbon, etc. Iodide will help a bit, but what you really want is to add a chloride, i.e., a ClBr paper. Kodabromide was a ClBr paper and was pure bromide paper's successor. The crisper blacks and greater contrast fit the evolving photographic tastes of its time (just as today the hyper-sharp and HDR'ed images are becoming the predominant expectation). A ClBr paper is a bit slower than a bromide paper, but with printing that hardly matters. The very crispest (and slowest) is a pure chloride paper, also known as "gaslight" paper. Go here: http://www.blurb.com/books/6465389-the-light-farm and read the three paper recipes for more information.

 

[dwross]

I'm not a big fan of rough paper. It obscures the detail of the print and detail is so much of the strength of silver gelatin negatives. With few exceptions, I print on HP ("hot press") watercolor paper. Arches 140 lb is probably my favorite. It is smoother than cold press yet still has enough tooth to coat easily and give character to the final print. Ultra-smooth commercial baryta is horrid stuff (one person's opinion, of course!). Coating it is not for someone brand new to coating. Coated well, with a good emulsion, is it indistinguishable from a commercial RC print. I can't imagine the point of making one .

Your cat print is gorgeous!

 

[A Joe]

For printing I used your I heart, it is lovely. I just prepared a plain sea water + nitrate before leaving, it's awaiting for me in the fridge

 

[dwross]

That's very, very nice to hear. Thank you.
Looking forward to hearing about your sea water emulsion. You and John (jnanian) will want to compare notes!