Rockland Colloid - Should I bother?

[DonF]

Thanks! It's great to plant a seed where you can. In our case, I'm more technically oriented, where she has the artistic eye. A good combo.

Congrats on your son's career. It feels great when an idea takes root!

Best,

Don

 

[DonF]

Well, we shot the thicker AG Plus emulsion, poured at 110 degree F and chilled with the pizza stone. The emulsion was much thicker and the development and fixing times were dramatically increased. The contrast also seems to have decreased. The one advantage was that the bubble problem was almost entirely eliminated. The frilling or emulsion shifting/lifting causing an uneven, grainy dried surface is still a problem. I think I will try "subbing" the plates with a plain gelatin solution to prime the very slick trophy engraving metal. Rockland recommends this for using AG Plus on glass/ceramic. It may help here with the frilling. I'm thinking it will be equivalent to multiple coats of AG Plus, while saving on the emulsion use.

Anyway, here are a few results. Not too bad...

Don

 

[removed account4]

these are really beautiful !

have you put a few drops of photoflo in the emulsion before you pour it ?
if you want a thin coat that might help get rid of some of the bubbles ( if you don't stir it up and make them that is )

 

[DonF]

Read my mind! My photoflo arrived yesterday. I forgot how wonderful that stuff is! I plan to do just that. I think the thinner emulsion was better, except for the frilling issue...and bubbles. Just tapping the container of emulsion when liquid seems to generate 'em.

Here's the results of my gelatin subbing exercise this morning. I level teaspoon sprinkled on top of 1 cup of cold water, sits for 5 minutes, then heated to lukewarm/hot and stirred to dissolve. I added maybe 5 drops of Photoflo. I scrubbed some reclaimed trophy plates in "Oxyclean", rinsed well, dipped in Photoflo solution, dried, and poured on the somewhat cooled gelatin. It spread like a dream, very smooth. I poured off the excess and put on the cookie cooling rack to dry. The plates were completely dry to touch in an hour. I did not add any chrome alum hardener to the gelatin as is done for wet plates, but Rockland did not mention including it. From the colored fringes, you can tell the subbed coating is quite thin.

 

[DonF]

This is the emulsion shifting and lifting I hope the gelatin subbing will help....

Don

 

[Photo Engineer]

Try Chrome Alum in the emulsion itself or in the subbing. This might help.

PE

 

[DonF]

Thanks. It looks like I do have an adhesion issue on the trophy plates with the AG Plus. I warmed the teddy bear plate slightly, as I was going to try applying some sandarac varnish. The emulsion literally popped off the plate with an audible snap. Two other plates are delaminating beneath the emulsion from normal handling. Hopefully the subbing will help. Trying those tomorrow.

Don

 

[removed account4]

hi don

when you clean your plates does water "sheen" off of the plate and not get "stuck" on the plate ?
i used washing soda / baking soda and a brush to scrub my plates to get them free of stuff that would have
given me problems. are you using food grade gelatin ? i used food grade for years but always put more in my sub
( i have hard bloom now but haven't taken it out of the box/tub ) ... what i do when i coat is make sure my pizza stone is
frozen solid and i pour our of a glass jar and get the run off back into a container, put it on the stone so the gelatin sets fast
and a little while later i put a 2nd coat on it. the 2nd coat always flows perfectly. have done this with 8x10 glass and as small
as 1/4 cut 4x5 plates. i also put hardener in my fixer because it cuts down on problems too.

you are getting such great results otherwise !
these plates of yours are great

john

 

[DonF]

Less emulsion irregularities with gelatin subbing. I'm going to try a few coats of gelatin. Generally, much better emulsion finish after drying.

John, yes, I scrubbed with detergent until zero spotting after rinse. I am using food grade gelatin. I have not tried the second coat, but I did use the frozen pizza stone trick on the one coat, which worked well. Getting there! Probably the best contrast yet on these two.

I also calibrated my Dad's old GE PR-1 selenium light meter with a blue filter across the lens. It is surprisingly usable for the tintypes. All our exposure times were good with an assumed ISO of 1.5. Shot mostly at f/11 today. I also applied exposure correction for bellows extension > 8 inches with my 210mm lens for closeups.

Don

 

[Photo Engineer]

Food gelatin might be the problem. It generally has additives (listed or not) and has the wrong viscosity.

For good coatings you need a BI (Bloom Index) 250 gelatin or thereabouts.

PE

 

[removed account4]

Less emulsion irregularities with gelatin subbing. I'm going to try a few coats of gelatin. Generally, much better emulsion finish after drying.

John, yes, I scrubbed with detergent until zero spotting after rinse. I am using food grade gelatin. I have not tried the second coat, but I did use the frozen pizza stone trick on the one coat, which worked well. Getting there! Probably the best contrast yet on these two.

I also calibrated my Dad's old GE PR-1 selenium light meter with a blue filter across the lens. It is surprisingly usable for the tintypes. All our exposure times were good with an assumed ISO of 1.5. Shot mostly at f/11 today. I also applied exposure correction for bellows extension > 8 inches with my 210mm lens for closeups

every post with plates you make is better than the last. im not sure if you did anything when you scanned them, but they sparkle on my monitor.
yeah, i'd do 2 coats of your knox gelatin and see how that works. one thing i do is instead of using a whole plate, i cut one in quarters
and stick them in my pentax k1000, its a perfect fit and there is less waste. while 250 bloom / hard bloom is usually said to be the best to use for
liquid gelatin and emulsion making, it can be done OK with food grade. i've used knox on and off since 1986 with my plates ( mostly glass )
and even cyanotypes ( haven't done it with cyanotypes on glass yet but that might be next ) without issue,
and some of thesmall plates i made ( glass internegatives ) look as if i made them yesterday .. if knox is what you have, double coat might do the trick ... when i made my sub layers, i never measured the water
and just dumped a package in water, maybe that made a diference.
hope it works for you, cause if the next batch tops this one its gonna be really nice !
==
i've always heard about using a blue filter ( from the someone who was involved with "luminous" emulsion in the 80s/90s, ) but he weasn't very clear about darkness of the filter and said " any old blue filter will do" but i have some dark ones and light ones ... which on do you have on your meter? a blue
one that can be use for rgb color separation, or something a bit lighter?

john

 

[DonF]

John, I did adjust the "exposure" setting on the scans in Photoshop, but that's about it. Otherwise the tintypes seem to render far too darkly.

Those last two startled me coming out of the developer. I really nailed the exposure on those. Great contrast with the thin emulsion, minimum frilling.

The plates have proved very easy to recycle! A dip in hot water a minute or so and a bit of scrubbing with finger tips and the emulsion slides right off. My Graflex Graphic View and Brownie are my only two tintype-capable cameras at the moment.

After the first two great plates, I started leaving them on the heating bad a minute or so after coating. Big mistake. The emulsion became far too thin and started tearing over the subbing. I think warming the subbed plates before the pour is ok, but I got best results by putting directly onto the cold pizza stone after coating. The photoflo in the emulsion seemed to really help as well, but may have hurt when I continued to heat the plates after the pour.

The blue filter on the light meter....Yes, I saw the "any old blue filter" instructions. I'm using a transparent blue file folder tab trimmed to fit the lens on the GE PR-1. The PR-1 goes down to ISO .6, I believe. It is a self-powered selenium meter, like most of the era. I have two or three Iphone light meter apps that seem to agree with the PR-1 pretty well with the same filter added, at least the ones that average the light from the scene. I;m using an ISO of 1.5.

I'm experimenting with some simple studio lighting and a few 100 watt (400 watt incandescent equivalent) daylight color temperature spiral fluorescent bulbs this week. Those babies are huge.

Removing the "haze" filter from the Scneider camera lens seemed to increase exposure by 1/2 to 1 stop as well.

So going to double and triple coat a few plates with the food grade gelatin for now, eliminate the post-pour plate warming and see what happens. I may try Photo Engineer's suggestion of adding chrome alum to the subbing gelatin, but none on hand and just placed an order with Photographers Formulary for the developer chemicals. I may try some spray acrylic, as others have reported good results. Perhaps increasing the drying time for the emulsion would help as well. I've been drying overnight and the plates are completely dry to the touch.

I will be out of the first 8 oz. bottle of emulsion this week, more on order.

I am finding this very enjoyable.

Thanks for taking the time to comment.

Best,

Don

 

[richyd]

Very nice results. I started experimenting with this last summer. The Rockland kit is not available in the UK but I have some very thin aluminium sheets, I think they were used for offset printing, are about the same as sheet film so fit easily in holders. I sprayed them with a black enamel, cut to 4x5 size and coated with Foma emulsion. I scoured threads to work out the process and to create a developer. It all worked surprisingly well though I thought the results could be a bit brighter. I played around with different developer formulas but it was hard to keep track of the effects as the process is quite variable anyway.

What I learned was:
1) For me the black enamel type had more of an effect on peeling emulsion than subbing, so in the end left out the subbing just making sure the plates were really clean. I think I gave a final rinse with distilled water and photo flo. The enamel that worked best though tends to orange peel when spraying.

2) When the weather became cooler and damper, the pictures came out with a bloom. I though at first it was a developing problem but now think it was due to humidity. I also noted that it took much longer to dry the plates. I dry them in a metal box film changer I have which has a ventilation hole, and made some racks to fit inside. I attached a small fan to the hole to extract air but will also need heat if it gets cool.

For coating I kept the emulsion warm and heated the plate with a small hair dryer then poured the emulsion in the centre, rocked the plated towards each side using a finger to even out any patches then letting any excess drip from each corner. Oh, I used Photo Flo from the start.

I had a few plates left over from last summer and tried one out a few days ago and to my surprise came out fine, which is interesting as I understood the that they would not keep once coated. Will try the other two remaining this week maybe with some developer tweaking when I find my notes.

 

[removed account4]

and coated with Foma emulsion

that is what i have at the moment to use up.
are you single coating the emulsion or putting more than one coat ?
the people at rockland told me if i wasn't using silver-rich AG+
the plates would come out better if double coating ..

john

 

[bvy]

Happy to send you some chrome alum. PM me!

 

[richyd]

Yes, I used Foma emulsion with a single coat, works very well. I think Rockland might be referring to their own Liquid Light which I'm sure I read on some forum somewhere needs a double coating.

 

[removed account4]

Yes, I used Foma emulsion with a single coat, works very well. I think Rockland might be referring to their own Liquid Light which I'm sure I read on some forum somewhere needs a double coating.

it might have been me.
i didn't use AG+ until recently but their VC and grade 3 liquid light ( expired ) emulsion needed a 2nd coat.

 

[DonF]

I found my old GE PR-1 selenium light meter to not provide sufficient sensitivity in low light. The Iphone apps seem kind of ok, but not very convenient to keep the blue filter slid between case and phone. I picked this Gossen "Luna-Lux" behemoth light meter up for a good price...60.00 USD, with original box, case and manual. It looks almost new.

The meter was Gossen's cost-reduced version of the Luna Pro SBC. I uses three LEDs for a center-null type of operation. It uses a standard 9-volt square battery. It covers an incredible 0.8 - 100,000 ISO range and shutter speeds from 8 hours to 1/4000 second. .35 to 35K footcandles. No flash control or measurement. The only downside is that it is huge! I like it because it uses an silicon photodiode and fairly modern circuitry in an old school design. The manual is a course in light meter theory in itself.

Don

 

[DonF]

My daughter and I did quite a bit of experimentation yesterday, now starting on our second 8oz bottle of AG Plus emulsion. We tested two new methods of preparing the glossy black plates from Main Trophy Supply. The single subbing coat of unhardened gelatin directly over plates scrubbed with washing soda (sodium carbonate) and rinsed was partially successful. A double coat of gelatin resulted in the emulsion completely floating off the coated plate in the wash water.

This time I tried lightly sanding the entire surface of the glossy plate with 1200 grit wet/dry sandpaper (the black stuff), followed by the sodium carbonate wash and rinse. I sprayed several of these prepped plates with oil-based glossy clear acrylic spray and allowed them to dry very thoroughly.

The sanded and washed plates performed the best I have seen. There was no sign of emulsion lifting at all. There was some reticulation of the emulsion here and there, but overall much less than before. I think this will be my standard plate prep going forward.

The sanded plates that were sprayed with the clear gloss acrylic were a complete fail. The hardened emulsion floated completely off the plate in the wash water. I was actually able to re-attach the film to the plate, dry, and get reasonable adhesion though!

I also found that reticulation seemed related to the exposure of the plate. Even moderate overexposure caused an extra thick coating of the white emulsion to remain, which eventually dried with a rough, although undistorted, surface. Some of this is in evidence on almost every plate we have done. Even 1/3 stop over exposure can tip the plate into the area of reduced contrast and increased reticulation. I've also seen it on most examples of other's plates. A very simple solution is to post-coat the thoroughly dried plate with two coats of clear gloss oil-based acrylic spray. This fills in the roughened emulsion areas and leaves a nice overall gloss finish on the plate. I have seen no negative effects of the coating on the developed plates. The coating also seems to prevent humidity absorption which can cloud the dried plates a few days after they dry.

Another win was determining that my homebrew developer performs identically to the Rockland formulation in all respects.

We also tried our first indoor exposures with a cheap $50.00 lighting kit from Amazon with the key and fill lights fitted with 400-watt equivalent daylight compact fluorescent bulbs. We got excellent results with reasonable exposure times of 35 seconds at f/16 for a tight portrait shot.

I'll post examples a bit later.

Best regards,

Don

 

[DonF]

Left portrait is with indoor lighting, 400 watt daylight fluorescent compact bulbs each for key and fill in umbrella reflectors. 200 watt back light. 1:1 flat ratio. f/16 at 35 seconds.

Both plates are developed with my home brew reversal developer. Both images are on the Main Trophy Supply "bright black" plates, sanded with 1200 grit paper, washed in washing soda and dried before coating. Plates were heated on heating pad before pouring AG Plus. I added 2 drops of photoflo to enough emulsion for 6 plates in a small beaker before pouring. Emulsion was heated in a 110 degree F water bath. Too much photoflo results in too thin coverage. Emulsion chilled on frozen pizza stone after pouring, then dried for 18 hours.

If any bubbles were on a plate after pouring, I found that I could use a toothpick to guide them to the edge, while returning plate to heating pad to keep emulsion liquid.

3 minutes processing time with 10 minute fix in Kodak hypo "Professional" hardening fixer and 10 minute wash.

Plates were dried overnight, then sprayed with three coats of gloss oil-based clear spray. This filled in any emulsion irregularities and rendered a nice even plate. Contrast was enhanced with no visible degradation of the image.

Tatoos do not show well on the emulsion in daylight.

Best,

Don

 

[DonF]

Three exposures about 1/2 stop apart with the artificial light setup shown:

 

[DonF]

A few more...

 

[richyd]

"The sanded plates that were sprayed with the clear gloss acrylic were a complete fail. The hardened emulsion floated completely off the plate in the wash water. I was actually able to re-attach the film to the plate, dry, and get reasonable adhesion though!"

Hi Don, last year when I was spraying my plates black I experienced emulsion lift with an automotive spray, possibly acrylic based, but with, I think, a polyurethane based paint paint adhesion was excellent. The brand of paint I used was Plastikote which I believe is a US brand. If your plates are already black then maybe they do a clear varnish was well or look for an equivalent or paint the plates with a similar black paint.

Good luck
Richard

 

[removed account4]

a polyurethane based paint paint adhesion was excellent

in the 80s, they used to recommend ( maybe still do ? ) using minwax polyurethane as a sub coat for glass plates.
the problem i found was that it yellowed over time ... it makes sense that urethane worked for the metal plates.

 

[DonF]

I spoke with the older Bob at Rockland on Monday, explaining what I had tried for the glossy Trophy plate preps. He said that no canned spray varnish of any type should be used to prep the plates to receive the gelatin. If a clear undercoat is desired, only a brush-on polyurethane is recommended. Apparently the propellants and solvents in the canned sprays affect adhesion.

He did say that it was OK to use spray acrylic varnish as a top coat over the developed and thoroughly dried plates. I have been doing this for a week or so with excellent results.

Another tip on coating the plates...I found that if the plates are warmed on a heating pad before coating, any visible bubbles after spreading the emulsion can be guided to the edge and popped with a toothpick. Any mars to the gelatin surface will heal after returning to the heating pad for a few seconds. A drop or two (no more) of Photoflo mixed gently with enough emulsion in a small container to coat six plates helps with even spreading and bubble reduction.

Extending my drying time of the coated plates from overnight (8 hours) to 24 hours seems to help with emulsion irregularities during processing (frilling, reticulation).

Don