Dry Plate Newbie

[Herzeleid]

Of course this is not staining, but the color of the dye blocks some UV light like the color from stain. This is more like a color filter.

 

[Photo Engineer]

Well, you likened it to staining, so I was not sure.

Yes, these are filters.

PE

 

[Herzeleid]

Update on my progress.

This time I meticulously monitored the temperatures of silver nitrate and salted gelatin before mixing and temperature during ripening, digestion. In hopes of eliminating the possibility of dead grains.
As Ron Mowrey suggested I initially used D76 1+1 (ID-11 to be precise) for testing the development and exposure.

I coated some 10x10" plates with 20ml and some with 25ml to compare densities. 25ml was easier to coat such large area.

I have reduced the amount of chrome alum to a quarter of its recommended value. No subbing on glass.

Exposed the plates as ISO 3 with blue rich CFL bulbs.
I started seeing developer action on plate within a minute, glass cleared at most in 3 mins during fixing.

I haven't observed any frilling, so I believe the amount of chrome alum is still good enough.

Later I switched to home made Rodinal 1+25 as developer and no pepper grain, tested 3 plates with PaRodinal. Looks dense enough, though I haven't measured it.


So it seems for this particular photo-grade gelatin chrome alum was really getting in the way.

Thanks everyone for their valuable input.

 

[removed account4]

Update on my progress.

This time I meticulously monitored the temperatures of silver nitrate and salted gelatin before mixing and temperature during ripening, digestion. In hopes of eliminating the possibility of dead grains.
As Ron Mowrey suggested I initially used D76 1+1 (ID-11 to be precise) for testing the development and exposure.

I coated some 10x10" plates with 20ml and some with 25ml to compare densities. 25ml was easier to coat such large area.

I have reduced the amount of chrome alum to a quarter of its recommended value. No subbing on glass.

Exposed the plates as ISO 3 with blue rich CFL bulbs.
I started seeing developer action on plate within a minute, glass cleared at most in 3 mins during fixing.

I haven't observed any frilling, so I believe the amount of chrome alum is still good enough.

Later I switched to home made Rodinal 1+25 as developer and no pepper grain, tested 3 plates with PaRodinal. Looks dense enough, though I haven't measured it.
View attachment 198235

So it seems for this particular photo-grade gelatin chrome alum was really getting in the way.

Thanks everyone for their valuable input.

beautiful image !
im glad you figured it out,
the image is a real treat to look at !
is this a glass positive ?
john

 

[Herzeleid]

beautiful image !
im glad you figured it out,
the image is a real treat to look at !
is this a glass positive ?
john

I shoot the same stuff on my bookshelves to compare, as I am still learning.
No, it is a negative actually, I inverted it digitally on the phone.
Thank you.

 

[Nodda Duma]

Looks great! -Jason

 

[Herzeleid]

Hi there,

After reading many of the post over and over again, I recently realized deciding how much to coat on a plate by volume might not be very healthy approach. Since I do old school noodle washing, gelatin will absorb some water and this will dilute the emulsion. How much it will be diluted after washing and draining, it is not controllable.
Wrapping the noodles in filter paper to absorb excess water is a possibility, or putting the noodles in a desiccator bag might work but I fear these methods might remove too much water from the noodles. This time I might be left with concentrated emulsion.
I might press the ball of noodles to remove much water as possible, or leave it to drain for an hour or a day, these worked well so far. So I can stick to one of these methods and find a sweet spot by trial and error.
But that does not help me understand the reasoning behind it.

So let's assume I am using Plain KBr I formula from the light farm. In total the mixture of liquids and solids before washing should weigh approximately 133 gr.
After washing and removing nitrates and extra bromide it should weigh slightly less than 130gr, but that won't be the case. The gelatine will absorb some water, who knows how much?
After measuring the final weight I should decide on the amount of coating gram per cm square according to the silver content. Am I correct?

How do you calculate how much to coat per plate? I recall reading PE mentioning 300mg silver metal per sq foot, but I do not know if that amount is for prints or plates.

Regards

 

[Nodda Duma]

I just keep track of total volume before and after washing, and then add back gelatin to get to the original percentage.

As far as how much to coat per plate: Hard-earned experience. Use about 0.25ml per square inch to get a good coating. Trying to set the silver concentration with coating thickness is the wrong approach because tge thickness has a far greater impact on the coating quality. Too much emulsion and you’ll waste emulsion and it’ll take forever to fix. Too little and you won’t get a good coating.

 

[dwross]

Jason is right. Experience, and then consistency is the key to repeatable nice plates. Some recipes call for "make-up" gelatin; others don't. Find a good recipe and then trust it. My KBr recipe is carefully calibrated so that adding gelatin after washing is not necessary. Squeezing the bag of noodles brings the gelatin-to-water ratio to the right place. If you feel it helps, you can follow up the squeezing with wringing the bag gently in a folded bath towel. Again, consistency is key. Since there are so few steps in a basic negative recipe, consistency isn't hard to manage. If you feel like your coating is too thick, raise the coating temperature just a bit. If it's too thin, cool it a bit. Don't forget to take room temperature into account. Keep a notebook. Once you know what works, stick with it. It does seem like you're having great luck!

 

[Herzeleid]

I just keep track of total volume before and after washing, and then add back gelatin to get to the original percentage.

As far as how much to coat per plate: Hard-earned experience. Use about 0.25ml per square inch to get a good coating. Trying to set the silver concentration with coating thickness is the wrong approach because tge thickness has a far greater impact on the coating quality. Too much emulsion and you’ll waste emulsion and it’ll take forever to fix. Too little and you won’t get a good coating.

I will definitely start tracking masses or volumes can't decide yet which one would be more effective. Lucky me, 0.25ml per inch square is identical to what I use currently.

But let's assume that I have a diluted emulsion, let's say 250ml instead of 150ml. By adjusting gelatin I would be aiming at a similar viscosity, but I would be coating less silver if I keep the volume per plate identical.
If I added gelatin to adjust viscosity, and I increase the coating volume per plate to compensate for extra water, I will be leaving more gelatin per inch square.
Eventually water will evaporate, and it will leave behind a certain amount of silver and gelatin.


Thanks a lot,

 

[Herzeleid]

Jason is right. Experience, and then consistency is the key to repeatable nice plates. Some recipes call for "make-up" gelatin; others don't. Find a good recipe and then trust it. My KBr recipe is carefully calibrated so that adding gelatin after washing is not necessary. Squeezing the bag of noodles brings the gelatin-to-water ratio to the right place. If you feel it helps, you can follow up the squeezing with wringing the bag gently in a folded bath towel. Again, consistency is key. Since there are so few steps in a basic negative recipe, consistency isn't hard to manage. If you feel like your coating is too thick, raise the coating temperature just a bit. If it's too thin, cool it a bit. Don't forget to take room temperature into account. Keep a notebook. Once you know what works, stick with it. It does seem like you're having great luck!

Thanks Denise,

I am taking notes of the procedures and I also monitor the room temperature and humidity, though my control is limited. Consistency is paramount I agree
I measure and aim to coat the same volume on all plates. That is actually why I ask this question.
It might happen one day the washed emulsion might weigh more than previous washes. I would have to compensate the coating volume per plate for it.
I understand from Jason's comment solely depending on silver concentration is not ideal, so there must be a correlation between gelatin and silver per inch square. ( I wish that was metric square )

 

[Photo Engineer]

I weigh before and after washing and add the amount of gelatin needed for the correct concentration. I try to aim for a middle weight of 8% by weight, or 8 g of dry gelatin, in 92 g of emulsion for a total of 100g.

PE

 

[Herzeleid]

I weigh before and after washing and add the amount of gelatin needed for the correct concentration. I try to aim for a middle weight of 8% by weight, or 8 g of dry gelatin, in 92 g of emulsion for a total of 100g.

PE

8 percent by weight is more viscous than the formulas I have used up to date. They are around 5 to 6 percent gelatin. Is there a special reason why you choose more viscous emulsion?

Thanks a lot

 

[Nodda Duma]

8% will suspend larger grain (a lesson learned the hard way) and the viscocity is different. I run 5-6% but would go higher if I changed my coating methods.

 

[Herzeleid]

8% will suspend larger grain (a lesson learned the hard way) and the viscocity is different. I run 5-6% but would go higher if I changed my coating methods.

Ohh, the cause of swirly patterns was that?

 

[Photo Engineer]

I use 8% for hand coatings because it is a happy middle ground. Not to thick and not too thin. Just right.

If you coat using machine or doctor blade, you have even more latitude due to the ability to vary gap width and coating rate.

PE

 

[Nodda Duma]

Ohh, the cause of swirly patterns was that?

Sort of. The screwball ripening times created grains larger than the gelatin could emulsify

 

[Herzeleid]

I use 8% for hand coatings because it is a happy middle ground. Not to thick and not too thin. Just right.

If you coat using machine or doctor blade, you have even more latitude due to the ability to vary gap width and coating rate.

PE

I will certainly try %8, I had no problems when hand coating glass with %10 gelatin to use with alternative process printing. May be %8 will give similar feel.

 

[dwross]

Give careful consideration to which variables you choose to manipulate. If you add extra gelatin to watery noodles, you will significantly change the silver ratio of the emulsion. This can be consequential. Perhaps a better idea to try (at least first) is to wring a bag that is heavier than usual in a clean bath towel. A couple of times, if necessary. If that doesn't bring your water weight to within your normal parameters, something else is going on. Dumping in extra gelatin (in a recipe that doesn't call for it) will not likely be a solution. (2 cents, and many years experience) d

 

[Herzeleid]

Give careful consideration to which variables you choose to manipulate. If you add extra gelatin to watery noodles, you will significantly change the silver ratio of the emulsion. This can be consequential. Perhaps a better idea to try (at least first) is to wring a bag that is heavier than usual in a clean bath towel. A couple of times, if necessary. If that doesn't bring your water weight to within your normal parameters, something else is going on. Dumping in extra gelatin (in a recipe that doesn't call for it) will not likely be a solution. (2 cents, and many years experience) d

Thanks Denise, I think my emulsion isn't diluted too much this time, but I was wondering how much water is absorbed by gelatin. From now on I would keep notes of before and after wash weights of my emulsion to determine and control this variable.

I just liked the idea of thicker gelatin, it flows and settles much better. But, I have to test erythrosine and S-Au sensitization this time. But suddenly this dilution problem was stuck in my mind while I was making calculations.
All these changes in gelatin and checking pre and post weights of emulsion will have to wait for the next batch.

 

[dwross]

Good luck with the sensitization! You're getting into the fun stuff!
and re viscosity: remember that cooler emulsion is thicker emulsion. You might try playing around with coating temperatures. Easy to do (even within the same batch) and doesn't mess with the basic characteristics of an emulsion.

 

[Herzeleid]

That is actually quite a good idea but I fear when coating larger plates cooler emulsion can be a problem. I use a few 4x5 test plates, and the rest of emulsion is coated on 10x10 plates.
I usually aim to coat runny emulsion on warm glass then leave the plates on a leveled stand and let the emulsion gel.

 

[Herzeleid]

I was hoping to write sooner with my emulsion tests, but my latest two emulsions were fogged heavily.

Before that I tested erythrosine and steigmann's S+Au sensitization in separate batches, green sensitivity was low but it was there.
May be I should try adding some tartrazine to slow down blue sensitivity in future but that is another story.

When I combined erythrosin dyed emulsion with S+Au, I got very foggy results. I was to able to restrain it with KBr in developer but it was too much.
I thought it was faulty washing or too long digestion and sensitization with Steigmann's gold sensitizer. So I did another small batch much more conservative in digestion and sensitization periods, and it was fogged again.
I managed to get a good visible image in developer under 1 min when exposed as ISO 20, so I feel like emulsion works but it was eventually covered by fog.

I later tested my safe light with borrowing a multigrade paper from a friend. My safe light for collodion work was not safe enough for ortho work. I was using a yellow led light with rubylith over it.

So I hope I managed to make faster green sensitive emulsion. Anyway, I will sort the safe light issue and keep working.

Regards

 

[Photo Engineer]

I have used yellowish safelights.

There was no problem with Ortho sensitization.

PE

 

[Herzeleid]

I have used a LED floodlight with rubylith over its glass, it is an ordinary lamp with warm yellowish color.
Apparently one layer of rubylith wasn't enough.