first post on apug. experienced emulsionists, need some advice please.

[chris77]

hello apug forum!

a tiny introduction from my side.
i am a 37 year old artist living in paris and have been interested in working with photography since quite some years.
almost ten years ago i have been doing a little expo in vienna, working for the first time with the liquid emulsion by maco (rollei black magic/fixed grade).
the results were.. comme ci comme ca not too bad i guess..
as it was an off-space, the crowd appreciated the "imperfections" of still lifes directly printed on the shabby walls.

coming back to working with this technique now again, i am aiming for somewhat higher standard, and here comes my question(s), for which i am hoping to find some answers here.

using again black magic (variable grade this time) i have to say that i am not impressed with the tonal range of the emulsion.
i am using a durst m800 enlarger and 6x7 cm negatives developed in rodinal (with a wonderful rendition of tones) and dont want to give up hope yet to find a solution.
i am already using tetenal centrabrom, sacrificing some dmax, and a grade 1.5 filter (should going even softer help? i doubt it)

is there any advice from people having used other commercial emulsions or will making the emulsion myself give better results?
am i too spoiled from looking at photo paper and have to accept that a comparable tonality is impossible to reach with liquid emulsions?
does it have to do with the fact that these emulsions are not panchromatically sensitized?

have had contact with a technician at maco, it was his advice to try the less contrasty centrabrom, and i have to say that it seems to have helped a bit. but i am still not satisfied. ;(
he said that these emulsion are rather "hard".. hmm.

i would be very happy to get some ideas/tips on how to continue my quest to do better.
thanks and hello to all lovers of the silver grain out there

chris

 

[Sirius Glass]

Welcome to APUG

 

[mike c]

Welcome to Apug Chris, I have never used Black Magic emulsion, but if you are getting to contrasty results try using lower contrast negatives if possible.


Mike

 

[Photo Engineer]

Very often the surface on which you coat can affect latitude and tone. Dull surfaces tend to decrease latitude and dmax and thus tone scale.

Not much you can do except try coating more silver + gelatin to try to get a glossier surface and more dmax.

Not being panchromatic is not very important here.

Also, make sure that you are not losing emulsion during processing, nor losing it by absorption into your substrate. Porous surfaces tend to absorb emulsion and glossy surfaces like some plastics can allow the emulsion to wash off.

PE

 

[chris77]

Very often the surface on which you coat can affect latitude and tone. Dull surfaces tend to decrease latitude and dmax and thus tone scale.

Not much you can do except try coating more silver + gelatin to try to get a glossier surface and more dmax.

Not being panchromatic is not very important here.

Also, make sure that you are not losing emulsion during processing, nor losing it by absorption into your substrate. Porous surfaces tend to absorb emulsion and glossy surfaces like some plastics can allow the emulsion to wash off.

PE

hello photo engineer!

interesting reply.
if i understand you correctly, you are saying that it is rather a lack of silver (layer) and/or a matter of surface than a matter of choice of brand.

apart from being careful when (in case of test canvases) pouring the liquids (developer+hardener/water/stop/fix/water), are there other advices? is the silver effectively getting washed out of the coating, for example by washing for too long, even if the coating seems physically unharmed?

in any case, your reply has already given me good direction for further testing.
thank you very much!

chris

 

[chris77]

Welcome to Apug Chris, I have never used Black Magic emulsion, but if you are getting to contrasty results try using lower contrast negatives if possible.


Mike

hello mike!
thats a good advice and exactly what i am trying to do. the negatives i am using now are balanced and have a long tonal range.
i would love to make it available in the print, but maybe i have to start trying to go even lower on the contrast filters and give it a bit more silver and/or more exposure.
tx

chris

 

[Photo Engineer]

Chris, your emulsion must have a hardener, and you should use a hardening fix or the emulsion may wash off the surface of the substrate. Use either glyoxal or chrome alum to harden the gelatin and assure that no silver washes off.

PE

 

[chris77]

Chris, your emulsion must have a hardener, and you should use a hardening fix or the emulsion may wash off the surface of the substrate. Use either glyoxal or chrome alum to harden the gelatin and assure that no silver washes off.

PE

well, i have been following the advice given by maco with their product. the hardener they sell with it is meant to be used in the developer (it doesnt slow the dev down, checked it)
but i will try to harden the gelatin next time! that should be beneficial anyways.
can you tell me how to use chrome alum to add to the gelatin? and in which quantity?

btw, i have no problems with the fragility of the emulsion, i dont damage it in the processing. if you told me now that i am still losing silver even though the coating is undamaged - that would change things. but i couldnt imagine it..

 

[Jerevan]

Welcome! And keep on asking questions - and show us some results whenever you are satisfied (or not).

Here is a good book, to get you further along, in case you haven't read it yet: http://shop.silverprint.co.uk/Martin-Reed-and-Sarah-Jones-Silver-Gelatin/product/2121/2121/

 

[Photo Engineer]

Well, if you feel that no emulsion is washing off, then it may not be a problem. IDK.

However, for use of chrome alum, make up a 10% solution for use. Add 5 ml of this to every 100 - 200 ml of 10% gelatin before coating.

PE

 

[aRolleiBrujo]

(there was a url link here which no longer exists)

, Welcome to APUG!

 

[chris77]

thanks jerevan.
i might show results here, but more likely when satisfied and happy to share
so long.
chris

 

[chris77]

Well, if you feel that no emulsion is washing off, then it may not be a problem. IDK.

However, for use of chrome alum, make up a 10% solution for use. Add 5 ml of this to every 100 - 200 ml of 10% gelatin before coating.

PE

hmm.i am trying to figure out what you mean by 10% gelatin ...?
and what solvent shall i use to dilute? water? spirit?

 

[Photo Engineer]

A 10% solution of chrome alum is 10 grams of chrome alum in 90 grams of water. This is weight / weight. If you use 90 ml of water then it is weight / volume. Both are good as the error in this case is miniscule.

As for 10% gelatin, this is the same, or 10 g of gelatin in 90 grams of water. Thus, 2% gelatin would be 2 grams of gelatin in 98 grams of water.

The emulsion should tell you the gel amount per unit volume or weight. If it does not, then you should assume 10% because this is close to normal coating percentage for gelatin.

PE

 

[ME Super]

Welcome to APUG, Chris! If it's emulsion making you're after, there are several on this forum that know what they're talking about. PE is one of them.

 

[Photo Engineer]

Thank you.

PE

 

[chris77]

Welcome to APUG, Chris! If it's emulsion making you're after, there are several on this forum that know what they're talking about. PE is one of them.

There is no doubt about that !
i appreciate it very much to finally find experts in the domain.
thanks for the help and good advice.
c

 

[chris77]

A 10% solution of chrome alum is 10 grams of chrome alum in 90 grams of water. This is weight / weight. If you use 90 ml of water then it is weight / volume. Both are good as the error in this case is miniscule.

As for 10% gelatin, this is the same, or 10 g of gelatin in 90 grams of water. Thus, 2% gelatin would be 2 grams of gelatin in 98 grams of water.

The emulsion should tell you the gel amount per unit volume or weight. If it does not, then you should assume 10% because this is close to normal coating percentage for gelatin.

PE

thanks for the info.
you are right, i cant tell the gel amount in the product (maco claims high silver content but doesnt give other details).
good day to you.
c