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dwross
10-21-2009, 07:21 PM
As far as heating plates goes, Denise Ross uses a small food drier heater that is placed into a little plywood drying cabinet that she has in her darkroom. It's about a 1 or so square, and a few feet tall, and the food drier sits in the bottom. She then has shelves (or was it slots that the glass slips into) for the sheets of glass. She put them in and lets them get up to temp before she coats. It's a nice setup and takes just a little space from her darkroom.

Hopefully, Denise will swing by here and correct any errors I made in the description.

You did good, Kirk! And I do have a nice setup, if I say so myself :). I live in a climate that's decidedly chilly a good deal of the time. My little warming box just takes that chill off my plates. I don't think elaborate (i.e. expensive) heating devices are necessary for your glass plates. In truth, the real variable creeps in as you transfer your plates to the coating area. It's hard to even guess how many degrees are lost in the process. I go so far as to warm up my darkroom to about 72F before I start coating, and that seems to be enough to do the trick.

Far more important is keeping the emulsion temperature within a narrow range, and making each batch of emulsion small enough that you can get the coating done quickly. Emulsion continues to ripen as it sits. Too long in the holding bath and it can even start to fog. That's also the main problem with planning on re-using emulsion from a previous session. Even if you don't add hardener (and I don't to my negative emulsions), the re-heating process will significantly change the characteristic curve of finished plates.

d

Ray Rogers
10-21-2009, 08:41 PM
... a small food drier heater....

What is a Food Drier Heater?
Farm equipment or something like that?
What foods need dryers?

What is Harbor Freight and what sort of products do they sell?

Ray

dwross
10-21-2009, 09:10 PM
I figure this link is a natural to your location, Ray!

http://www.motherearthnews.com/Real-Food/2003-06-01/Choosing-a-Food-Dehydrator.aspx

Read about the convection style on the second page, and let Google do your walking from there.
d

willrea
10-21-2009, 09:11 PM
... a small food drier heater....

What is a Food Drier Heater?


Maybe something to dehydrate food?

Harbor Freight is a hardware store.

Kirk Keyes
10-22-2009, 12:17 AM
What is Harbor Freight and what sort of products do they sell?

Harbor Freight sells mostly imported tools. From what I saw, it's not near the quality of what you can pick up at Sears.

Anyway, the IR temp meter was inexpensive and works.

Kirk Keyes
10-22-2009, 12:18 AM
Maybe something to dehydrate food?

Yes, a food dehydrator. But Denise is using just the heater and putting that into a cabinet.

Ray Rogers
10-22-2009, 06:35 AM
Maybe something to dehydrate food?

Harbor Freight is a hardware store.

OIC.

I totally forgot about dried herbs, dried tomatoes, friut leathers, figs, apricots and so on. The pound or so of herb I might wish to dry just air dries naturally.

Ray

wildbillbugman
10-22-2009, 11:33 AM
In truth, the real variable creeps in as you transfer your plates to the coating area. It's hard to even guess how many degrees are lost in the process.

.................................................. .................................................. ..

Denise,
Have you thought about heating your coating frame? I use a coating frame similar to your`s. But I use oinly one glass frame for multiple plates. As I recall,you set up a frame for each plate. A small amount of heat, like a heating pad on low, under the frame would keep the heating frame at constant temperature. You could keep the plates in the dehydrater. Then transfer to the heated frame.
This is pure conjection on my part. I use one frame, unheated, for multiple coatings. I do not heat the plates
But the truth is: No matter what the coating method, I am a putz, no matter what the method.
Bill

dwross
10-22-2009, 09:23 PM
Hi Bill,

Before I coat my plates, before even I start melting the noodles, I arrange all the plates for coating. I set each plate on a piece of silicon matting that is in turn set on a piece of rigid acrylic. I surround each plate with four strips of glass to allow the emulsion well and coating rod to ride quickly and evenly over the whole of the plate. The strips stay in place until the plate is dry. They keep the emulsion from running all over the place before it sets up. I don't preheat the glass. I coat so quickly (2-3 seconds/plate) that room temperature glass is actually an advantage. By the time I have washed and dried the well and puddle pusher for the next plate coating, the plate I just coated has set up enough to carefully move out of the way for complete drying on a level shelf.

And you are not a putz. Far from it. You do remarkably well considering what your poor hands have been through. I keep trying to think of a way to make it easier for you. We'll come up with something.
d

studiocarter
10-23-2009, 08:34 AM
A water bourn clear coating might work.
Bill
Just got back and was very surprised to see so many posts??!!
Bill, from page 2: I tried that, ie. water based polyurethane sub coated glass, and the ENTIRE image lifted off into my hands. I'd dried the developed subbed plate in the oven because it had bubbled and lifted off the glass in room humidity. It is very dry in the oven because of the pilot light; it went flat; humidity in the room caused it to totally lift off even after it had gotten flat. It was flat long enough to scan into the computer.
Lifted off free emulsion pictures is something to keep in mind for very expirmental works. The emulsion, free from the glass, is very tough like leather and will not tear easily. It could be glued onto things.

wildbillbugman
10-24-2009, 03:37 PM
Studiocarter,
You may have misunderstood. I was not sugesting water based subing. I was sugesting water based EDGING, specificly for collodion. The idea is to have the collodion repelled by the coating at the edges only, not to coat the entire plate with water based subbing.
I dip the edges of each cleaned plate(wearing powder-free gloves) into hot wax.
When I pour my emulsion, the emulsion is repelled from the edges but adheres very well to the clean glass. Lack of adhesion of emulsion to glass is NEVER one of my problems.
Bill

wildbillbugman
10-24-2009, 03:55 PM
I keep trying to think of a way to make it easier for you. We'll come up with something.
d[/QUOTE]

Denise,
Think of a way to get me intrested in kniting or basket weaving, or something that dose not involve substances in a fluid state.
Every one else,
My recomendation for a waterbourne coating was specificly for Collodion. NOT for silver gelatin emulsions!
Bill

jnanian
10-24-2009, 04:20 PM
hi bill

you don't sub your dry plates ?
maybe i am misreading what you wrote, but you get your emulsion to
anchor onto the smooth glass surface without an intermediary layer for the emulsion to grab onto ?
i've never been that lucky ...

i've coated plates since the 1980s and in the beginning my biggest stumbling block was not knowing how to get the emulsion to stick the glass.
i had no problem getting the glass very very clean, but no matter what i did,
emulsion lifting off of the plate was always an issue.

in the end i was able to control the "lift" so i could make it happen when i
wanted it to and get a hand poured version of a polaroid emulsion transfer but on glass instead of on paper ...

Photo Engineer
10-24-2009, 04:29 PM
I don't sub glass plates and AFAIK, many brands of commercial glass plates were not subbed.

The key, I am told, is the chrome alum hardener.

PE

jnanian
10-24-2009, 07:25 PM
thanks ron!

john

wildbillbugman
10-25-2009, 12:20 AM
[QUOTE=jnanian;883088]hi bill

you don't sub your dry plates ?
maybe i am misreading what you wrote, but you get your emulsion to
anchor onto the smooth glass surface without an intermediary layer for the emulsion to grab onto ?
i've never been that lucky .
================================================== =======
Yes,
On The Light Farm website,I have an articlal that describes how I clean glass. I have been working with phographic images on glass for at leat 12 years now, and with silver.gelatin emulsion making for only two years. Cleaning is essential.
I do not always use hardener. And when I do it may be chrome alum or it may be glyoxal and even(Shhhhh!)formaldehyde. But no matter what hardener I use,or don't use, I Repeat, I never have frilling or lifting from the glass. Try my glass cleaning method.
Bill:rolleyes:

jnanian
10-25-2009, 12:45 AM
thanks bill
i think i will do just that,
thanks for letting me know about your article!

john

dwross
10-25-2009, 02:27 PM
I'd like to add my support for Bill's creds as a glass authority. I don't know anyone who has more experience with more processes on glass than Bill. When Bill talks glass, I know I listen. I will add, from my own experience with silver gelatin dry plate emulsions, glyoxal is only suitable if what you want is a beautiful emulsion transfer. Michael Carter is spot-on with that observation.

And, a short additional note about chrome alum. It certainly doesn't do any harm, but it really isn't necessary for most people making dry plates today. Back when, it was used by the makers of commercial plates mostly because they didn't know the temperatures people would be working with. Today, with A/C, ice cubes, and digital thermometers, we don't have to worry so much about summer darkroom conditions. The same goes for added preservatives.

There is a downside to adding alum, at least for beginning or casual plate makers. It takes at least a couple of days to fully work. If you know for an absolute fact that you have ripened your emulsion to precisely the right point, this is all fine and dandy. But, if you have passed even a little bit into over-ripening, your plates can pick up a bit of fog before the alum has completely cured. If you under-ripened, your plates may continue to pick up speed. If there is significant time between the time you expose and process the first plate in a batch and the last plate, they may be fairly different plates, which makes exposure testing harder than it need be.

So...my advice is to keep things as simple as possible. Make small batches of emulsion and make them often. Don't think in terms making 'enough plates to last awhile', at least as you are starting out. If ever an old saying was true, it's here. Practice makes perfect.

It's really exciting to see all the new work being done with emulsions, including PE's continuing research. It will be very interesting to read this forum five years from now!

d

keithwms
10-27-2009, 09:31 AM
It's really exciting to see all the new work being done with emulsions, including PE's continuing research. It will be very interesting to read this forum five years from now!

That's a very nice thought. New techniques will be available due to the hard work of all the thinkers and tinkerers, and I suppose that the analogue images will be even more distinctive and valuable.

studiocarter
07-02-2011, 07:58 PM
http://i822.photobucket.com/albums/zz148/studiocarter/Dry%20Plate%20Photography/031pos2.jpg

Liquid Light emulsion on glass 8x15 inches. F45 for 15 seconds with a big old brass lens in a Vageeswari Camera Works camera. Sun was 320 -1 block or 280 foot candles. Development was in Dektol 1:3 in 2 min 45 seconds.