Alternative issues

[Stephen Samuels]

Following on from my previous thread about cyanotypes (thanks again for all the responses), which i think is now solved (basically i just came to terms with the colour change!), i've got some other issues about iron-based alternatives.

I've been trying argyrotypes - again using the fotospeed pre-prepared sensitiser - along with Herschel paper from Ruscombe mill (the successor to Buxton) and a homemade lightbox comprising 8 x 600mm black light tubes suspended 6" above the print frame.

So my issues/observations are:

• my exposure times are ludicrous - others report exposures ranging from 3 to 10 minutes but i'm leaving mine in for an hour just to get something close to highlight detail. I'm driven to thinking the tubes are wrong somehow but they light up and glow blue and the print is very close to them so why the massive difference in exposure times? Incidentally, the area outside the negative reaches a dark blue/brown so it can't be the glass i'm using that blocks the UV.

• i double coat the sensitiser on Herschel paper, leaving it to dry thoroughly in between, and i've used large format (in camera) negatives with a density range of both 2.0 and about 1.4. The higher density range produces dreadful images with virtually no UV penetrating on the highlights so i get swathes of pure white in those areas (and that's after an hour!!) The lower contrast negative delivers a lovely soft image but that goes completely contrary to received wisdom. Not sure i get it. I've laid a Stouffer step wedge alongside every image (No 12115, 21 step) and get nothing beyond step 11 which i believe to be about 1.4 so that correlates with the negative.

• the Herschel paper - which i understood was exceptional for these processes - seems to 'pick up' terribly on the surface, so much so that the finished print has grey fibres all over it. The image also seems incredibly impermanent when you touch the edges with your thumb, it just wipes off although the residue seems fibrous so i'm assuming it's the paper that's coming apart not just the emulsion wiping off. Further evidence is in the thiosulphate fixer where a clear residue of bits is left after 3 minutes processing. I get a similar problem with cyanotypes with bits in the sulphamic acid solution i use. I brush coat the sensitiser using a good quality, and incredibly soft, water colour brush and do it very gently so i can't believe i'm picking up the surface as i do it.

I don't know what the answers to any of these are but i have to say, these processes are not as 'user friendly' as the internet would have you believe. I'm gradually examining each stage of my process to see where the problems might lie but from everything i've read on the subject, i can't see what i'm doing so badly as to cause all this.

Any thoughts/observations would be gratefully received.

Stephen

PS A quick update having re-read this - i use one or two drops of 20% Tween to every 10cc of sensitiser and the Stouffer reference above should have said step 10 for a relative density of 1.4 but the point remains the same.

 

[Ian Leake]

Hi Stephen, I can't comment on your argyrotype difficulties but I can comment on Herschel. This is a fabulous paper, albeit with quite a texture. I'm confident that what you are seeing is not caused by the paper.

My first thought is that you may be over-brushing the paper, possibly related to double coating and Tween20.

My second thought is that you may be using too strong acids in your processing. I've seen strong citric acid break up the surface of paper and turn it fibrous and fluffy, for example.

 

[Stephen Samuels]

Hi Ian, nice to hear from you (you probably don't remember but i visited your flat about 8 years ago and was deeply impressed by your work. Have just updated to edition 2 of your book which has been a great help).

Thanks for the suggestions. Yes, Herschel does have a texture that i'm not yet sure about aesthetically, but that's another question, and i take your point about over-brushing. I'm trying to be sensitive but it's a question of practice i guess. I started with the rod but that seems to grate on the Herschel texture (another reason for not being sure about it!)

As for the acid, i'm not sure where that would come into the process. I'm following Mike Ware's approach with a short wash, sodium thiosulphite fix, then a long wash. I'm not aware of our water being acidic to that extent but could check. I don't generally use distilled water because of the quantities required but filter everything down to 20 microns which has worked well for me so far. I never get spots on 10x8 negatives, for example.

Appreciate your help and keep up the good work.

Stephen

 

[Ian Leake]

Thanks Stephen, that's kind of you to say.

 

[Andrew O'Neill]

It's probably not the paper, if you say you are getting good exposure outside the negative area. Acidifying will increase dmax and reduce exposure time, but I know nothing about your choice of paper and how it would stand up to a bath containing 10% Sulfamic Acid. But you probably don't need to go there.
I have a BLB exposure table as well as a halogen vaccuum table. Kallitypes exposed with the BLB light takes about 15 minutes on Arches Platine. On the halogen, it takes 8. I don't even bother exposing carbon transfers on the BLB table. Exposures are 40 minutes and only 20 on the halogen... yes 20 minutes is long, but 40??

 

[ced]

Maybe the wiring is wrong reducing the intensity of the light output.
8 tubes should be very intense and so close to the paper my thoughts...

 

[Ian Leake]

A last few thoughts about Herschel. The optimum quantity of sensitiser is about 1.5ml for an 8x10. That amount will coat very smoothly with a 3" brush in only a few passes. If you use more then you'll likely have to wipe of some excess. If you use less then you'all get poor coverage.

TWEEN20 causes the sensitiser to be absorbed more, so you may need to adjust quantities if you use this nasty stuff. One drop diluted 1:3 with distilled water has a noticeable effect. Having said that, Herschel doesn't need Tween20, although you do have to leave the sensitiser for a while if it's going to bond properly with the paper fibres. I rest my sensitised paper in the dark for 10 minutes before using a hair dryer to finish. More time won't hurt, but I've found that less time is insufficient.

I've experimented double-coating Herschel (with platinum/palladium). I've not seen any benefits over a properly single-coated print, but I've seen problems caused by the second coating disturbing the first coating.

I wouldn't dream of putting Herschel in sulfamic acid.

 

[Ian Leake]

One other thought: how are you producing your negatives? What developer are you using? And are you using a densitometer for your density readings? A staining developer will give you misleading densities because most densitometers don't pick up the stain.

You could try developing an unexposed sheet of film and exposing it stacked with your step wedge. This will give you an idea of how FB+F is affecting the print.

 

[Stephen Samuels]

It's probably not the paper, if you say you are getting good exposure outside the negative area. Acidifying will increase dmax and reduce exposure time, but I know nothing about your choice of paper and how it would stand up to a bath containing 10% Sulfamic Acid. But you probably don't need to go there.
I have a BLB exposure table as well as a halogen vaccuum table. Kallitypes exposed with the BLB light takes about 15 minutes on Arches Platine. On the halogen, it takes 8. I don't even bother exposing carbon transfers on the BLB table. Exposures are 40 minutes and only 20 on the halogen... yes 20 minutes is long, but 40??

Thank you Andrew, i agree the times for BLB are odd. I need to work my way through the box i use to see whether it's tired ballasts or old bulbs that are doing it.

 

[Stephen Samuels]

Maybe the wiring is wrong reducing the intensity of the light output.
8 tubes should be very intense and so close to the paper my thoughts...

Perfectly possible. I need to get the meter out and check voltages through my wiring although, intuitively, i would expect the tubes not to strike if the electrode potential is too low, rather than just emit a proportionally lower output. But then i'm no fluorescent expert! Thanks for the suggestion.

 

[Stephen Samuels]

A last few thoughts about Herschel. The optimum quantity of sensitiser is about 1.5ml for an 8x10. That amount will coat very smoothly with a 3" brush in only a few passes. If you use more then you'll likely have to wipe of some excess. If you use less then you'all get poor coverage.

TWEEN20 causes the sensitiser to be absorbed more, so you may need to adjust quantities if you use this nasty stuff. One drop diluted 1:3 with distilled water has a noticeable effect. Having said that, Herschel doesn't need Tween20, although you do have to leave the sensitiser for a while if it's going to bond properly with the paper fibres. I rest my sensitised paper in the dark for 10 minutes before using a hair dryer to finish. More time won't hurt, but I've found that less time is insufficient.

I've experimented double-coating Herschel (with platinum/palladium). I've not seen any benefits over a properly single-coated print, but I've seen problems caused by the second coating disturbing the first coating.
I wouldn't dream of putting Herschel in sulfamic acid.

Thanks Ian. I've been using about 2.5cc for a 10x8, although admittedly covering the entire sheet - approx 11x9 - in order to give a margin for the step wedge. It's probably too much, as you suggest, and is a factor of my inexperience in coating. Anything less and i get dry areas on the paper using a 2" brush. I take your point on double coating too but i've no confidence yet of getting good coverage with just a single. I allow the paper to air dry in total darkness for a couple of hours between coats and it certainly feels dry enough when the second coat is applied. Maybe a hairdryer would add a belt to those braces.

As for Tween, i've only included as it's suggested by Mike Ware but will try without to see if that makes a difference.

 

[Stephen Samuels]

One other thought: how are you producing your negatives? What developer are you using? And are you using a densitometer for your density readings? A staining developer will give you misleading densities because most densitometers don't pick up the stain.

You could try developing an unexposed sheet of film and exposing it stacked with your step wedge. This will give you an idea of how FB+F is affecting the print.

I'm using Ilfotech HC (non-staining) in a JOBO processor, and use an RH Designs Analyser Pro for relative density readings. Taking readings from the step wedge gives results equivalent to the stated densities from Stouffer so i think i'm pretty much in the ball park. I'll try the unexposed sheet idea and see what that shows.

 

[Dibbd]

I only started with alt processes a few weeks ago so take what I say with the pinch of salt it deserves.

I suspect that your bulbs are part of the problem. I initially bought one of these: http://www.uvgear.co.uk/product/product234.htm

Supposedly 365nm, it took hours to expose a cyanotype. Absolute rubbish.

Then I got one of these. http://cyanotype.co.uk/uvlamp1.html

No idea what the bulb is, there's no identification on it, but I do get sensible exposure times now. The lighting is a bit uneven though. For the time being I'm moving the light a few times during the exposure to even it out.

I made my first argyrotype last Friday and got my first decent print (on Herschel paper) last night. I made the sensitiser up myself and I was having trouble with dark spots surrounded by a light area on my prints at first. Filtering the solution seems to have fixed that.

I find the exposure time is similar to cyanotypes. I expected it to be faster.

I've also found, again contrary to expectations, that it works perfectly well on cheap 200gsm sketch pad paper from Rymans.

http://www.ryman.co.uk/ryman-sketch-pad-a4-200gsm-60-pages-30-sheets

I'd suggest using something like that at first and save the Herschel until you get the other wrinkles ironed out.

I haven't had the Herschel paper fall apart as badly as you have but the surface is extremely fragile when wet and brushing too hard causes problems. I've only coated it a single time. I can imagine brushing a second coating on could damage it unless you are very careful.

I'm using digital negatives after calibrating my own curve. My curve isn't S shaped like most examples I've seen. I'm using a Canon Pro-1 for printing negatives though and everyone else uses Epson printers. Nevertheless, the curve is very steep in the shadows and much flatter in the highlight area. That kind of fits in with your observations with film.

 

[TheFlyingCamera]

Another thought on the timing - I'd try two things. One: move the lights closer to your printing frame. If you're hitting an hour with the lights at 6", moving them to 1.5" would get you into the under-15 minute range. I get 6-24 minutes times with platinum/palladium prints depending on the exact emulsion mix I'm using and the density of the negative with my lights about 1.5" from the top of the frame. Two: I've experienced that double-coating tends to slow my exposures down- if I single-coat, I'm somewhere in the 6-8 minute range, double-coating is a minimum of 12 minutes. Double-coating with platinum in the mix can run me up to 24 minutes. I don't know how fast argyrotypes are relative to platinum/palladium - they could be a slower, less-sensitive emulsion than Pt/Pd, so an hour could well be in the reasonable exposure range.

 

[TheFlyingCamera]

Another thought on the timing - I'd try two things. One: move the lights closer to your printing frame. If you're hitting an hour with the lights at 6", moving them to 1.5" would get you into the under-15 minute range. I get 6-24 minutes times with platinum/palladium prints depending on the exact emulsion mix I'm using and the density of the negative with my lights about 1.5" from the top of the frame. Two: I've experienced that double-coating tends to slow my exposures down- if I single-coat, I'm somewhere in the 6-8 minute range, double-coating is a minimum of 12 minutes. Double-coating with platinum in the mix can run me up to 24 minutes. I don't know how fast argyrotypes are relative to platinum/palladium - they could be a slower, less-sensitive emulsion than Pt/Pd, so an hour could well be in the reasonable exposure range.

 

[Stephen Samuels]

Hi Dibbd and many thanks for coming back to me.

Your experience looks interesting especially as i've had doubts about the tubes i bought too. I got them from eBay and they are unbranded so i am wondering if they're all they're cracked up to be. I've also been through my wiring with a multi-meter but, not being anything like knowledgeable about the workings of fluorescents, i picked up a voltage at the tube fitting that cycled once between three readings - something like 300V, 180V and 0V where it settled. I had read on line that tubes run at about 700V but i never got anywhere near that, nor did it stay at a constant operating voltage. I gave up after that as i had no idea what i was looking at. Anyway, the tubes and my bank in operation are shown below:

You can see some variance in tube luminosity but generally, they're all on!!

It seems the issue with Herschel paper was my vigour in coating and when i repeated it more gently, the surface remained intact so i think that problem is solved.

When it comes to exposure, i took your advice TheFlyingCamera and lifted the printing frame nearer the tubes - down from 6" to 3.5" - reducing the exposure time to 30 minutes from 60. I'm not sure i could go closer than 3.5" as my tubes are about 3/4" apart and the gaps may begin to show as uneven light? I also used one single coated sheet and one double coated.

The results were interesting in that:

• the single coated sheet has much less detail in the shadows than the double-coated but a more or less equivalent Dmax (although i don't have a reflection densitometer so i'm only working by eye). Not what i would have expected

• the single coated sheet also appeared darker all over with darker highlights, once again not what i would have expected

• the single coated sheet came out a much warmer brown (burnt umbra from my watercolour days?) whereas the double-coated sheet was close to a conventional chlorobromide paper; no idea why there would be such a colour shift - the double-coated paper also processed quite badly with grey patches where something appears not to have processed properly (see an example above the righthand squash in the second image - squash itself is not blotchy as it appears in the image, that's a factor of a quick digital photo)

I've attached examples to illustrate my results, including the Stouffer wedge from the single coated sheet showing nothing north of step 11. The negative i used had a density range of 1.4, much less than recommended for these processes.

Single-coated paper image:

Double-coated image:

Single coat step wedge:

Thanks again all for the advice and support - i'll plough on and see where i get!

Stephen

 

[TheFlyingCamera]

I'll look at my setup when I get home and measure from center to center of the tubes but I'm pretty sure they are more than 1" apart and I have no banding issues.

 

[Stephen Samuels]

Thanks, that would be useful to know.

 

[Vaughn]

Deleted quote and reply...being wrong is a sob!

I prefer the BL tubes over the BLB tubes-- cheaper (no filter in the bulb to block white light), but I never tested if they were any faster. I am presently using mercury vapor lamps (750W to 1000W).