Monday, 28 February 2011

Field trip to the Roaches

We went to the Roaches yesterday to spend the afternoon using large and medium format cameras in the dramatic rocky landscape.

It rained.  By about 3 o'clock the weather broke and the sun came out for a while, then it got cold again (it even hailed a bit!).  We packed it in at about 4:30, but I think the day was really good fun apart from the aching feet and knees!

Here's a few scans of some of the negatives that I made with my Bronica SQa and TMAX 400 B&W film.  All developed in Rodinal 1+50 for 11 minutes at 20 degC.

"It's supposed to clear by 3 o'clock" - it did! How did Lee know?

The Bawdstone near Hen Cloud



On top of the world?





 Two views of the Tittesworth Reservoir (?)



A good day out - thanks, Matt and Lee.

Finally - some darkroom printing at home

I finally got round to working out a practical method of blacking out my bathroom to make a home darkroom.

The next few images show how I have blocked out the window with insulation foam-board backed with shoe boxes!  A blanket over the door from the landing gives me (almost) complete blackout - good enough for lith printing development of 5-8 minutes during the middle of the day.

Boards over the bath under the light-proofed window

My little old Durst enlarger with a 6x6 colour head

Prints hanging to dry (or should I say curl)

I made about a dozen prints in my first printing session.  A sample of the results is here:

Long exposure (low contrast) on Fomatone MG dev'd in Rollei Vintage Lith

Same image - shorter exposure (higher contrast) on Fotospeed Lith paper
 dev'd in Rollei Vintage

Fomatone MG again, dev'd in Rollei Vintage

Clarence Mill on Fotospeed Lith dev'd in Fotospeed LD20

I'm quite pleased with the results.

Friday, 11 February 2011

Another session lith printing in the darkroom

This time I thought I would try the LD20 lith developer at a greater dilution and use it warm - so I mixed up a litre at 1+14 using water at about blood heat (37 degC).  I had to guess the temperature by feel as the darkroom thermometers only go to 30!

I had expected the results to be more 'lith like' but I feel the prints have come out colder than the ones last week when the dev was at 1+9 at 20 degC.  I really like the texture that has come out in the trees in this more contrasty print (originally exposed for 40s at f/8) - the more dilute developer gives a longer window of opportunity to choose a snatch point.

40s at f/8 - snatched when foreground tree texture was right
I revisited the garden shed/greenhouse negatives again.  I am producing multiple copies of all the lith prints both to experiment with the process and to provide material for subsequent toning sessions.

Exposed for 40s at f/8 - dev 1+14 at about 35 degC

Exposed for 80s at f/8 - dev 1+14 at about 35 degC

Anyway, I've ordered some more FB paper (Fomatone Nature MG) and a different developer (Rollei Vintage Creative Superlith).  When it arrives I'll see what the resulting prints look like.  It seems that all devs and papers give subtly different effects.

Ooh! The excitement!

Another go at the gum over cyanotype

After the last attempt, I decided that the orangey red highlights went well with the base cyanotype blue and I reprinted the negative as a slightly darker/crisper cyanotype.

This time I dressed the papaer over the top of the dried cyanotype with acrylic gesso and laid the surface off with clean water then allowed it to dry.,  The resulting slightly grainy surface provided a good key for the next gum layer.

After the last attempt, I realised that my gum was too loaded with pigment and this time I diluted it to the point that you could see the mixing dish through the colour.  Applying the sensitized gum to the gesso finish was quite easy and gave a nice, even finish.

5 minutes under the UV tubes and I put the print face down on a tray of warm water to develop.  After 20 minutes I drained it off and found that the highlights had a pleasant peachy hue and the shadows still looked reasonably blue.  A successful run, I think...

Thursday, 3 February 2011

More lith printing

Hey!  I think I'm starting to get the hang of this...

Another hour or so spent in the darkroom over a tray of warm LD20 developer, and I've actually got a set of prints which show some progress!

After last week's debacle, I decided to do all the exposures first, then develop the sheets one by one.  So I exposed 2 sheets of my "garden shed" negative for 40s at f/8 and another 2 sheets for 80s at f/8. I repeated the exercise for the "trees" negative.

The theory is that longer exposures flatten out the contrast, because the amount of light energy reaching the shadow areas of the negative reaches a point where more exposure does not cause any significant darkening of the blacks, but the less exposed highlight areas receive more light energy.  A more exposed sheet requires a little less developing time, but when the development is stopped the difference between the highlights and shadows is much less.  Conversely, a lesser exposed sheet will take longer to develop, but when the shadows are established, the highlights are only just beginning to fill in.  Here's an example of the visible differences:

40s at f/8 - stopped when foreground blacks looked right

80s at f/8 - stopped when foreground blacks looked right

You can see that the contrast on the 40-second print is much greater than the contrast on the 80-second one (look at the dark stains on the lower half of the door).  In both prints the colour is a sort of vintage albumen-print colour.  I will try some experiments in future with radically shorter exposures and more dilute developer.  The waiting time will be much longer but the colour effects should be more pronounced.

I only had time for one more print in this session, so I revisited the trees negative which I started with last week.  The following print is the longer, less contrasty exposure.  I am quite pleased with this and look forward to comparing it with the higher contrast exposure when I develop it, hopefully next week.

80s at f/8 - stopped when bark textures looked right

Monday, 31 January 2011

Attempt at duotoning a cyanotype with gum

Oh hum!  The theory was that I would take one of my cyanotype prints ( see Cyanotype - 28/12/2010 below) and, retaining the cyanotype blue in the shadows, colour the highlights with a purplish red.

So much for theory!  Despite pre-sizing the paper with a coating of uncoloured gum, and then using a very diluted pink and pale blue watercolour gum mix for the colour layer, I still have red staining across the whole image, shadows and highlights.

I suspect that my 'rose' watercolour pigment bites too well on the watercolour paper I am using and gets embedded in the paper during the washing phase.

Gum over Cyanotype





The basic technique is to coat the paper with a coloured gum arabic solution which has been sensitised with potassium dichromate solution.  Dichromates are not themselves sensitive to light but when mixed with some organic substances makes the mixture harden when exposed to ultra-violet light becoming nearly insoluble in water.  Emulsions made from gum arabic, potassium dichromate and colouring pigments can therefore be used to make a photographic positive from a negative by contact printing.

After exposure, the print is floated face-down in water to dissolve away the unhardened gum and wash out the unused dichromate from the paper.  What is left is the positive image exposed by the light.  This process is called by its traditional name of Gum Bichromate printing  (BIchromate was the historical name of what was later called DIchromate, but is now called Potassium Dichromate (VI) )

In this example, the cyanotype was produced from a negative, but the gum layer was exposed through a positive film, as I wanted to expose the highlights.  Ideally, the result should have been lilac/purplish tones through the highlight areas of the print.

Oh well - better luck next time!

Sunday, 30 January 2011

In the darkroom - Lith printing

This is something I've wanted to try for a long while - I've had the kit for about 15 months and not got around to it until this week's college evening!

Lith printing is a printing technique in which an image is overexposed by about 2 stops onto a fibre-based photographic paper.  The resulting image is then developed in a special 'lith' developer, based on Hydroquinone in a very alkaline solution.  The development process is 'infectious' which means that development starts first in the shadow areas, and as these darker tones start to emerge they develop even faster - the process causes the dark areas to become coarse and grainy whilst the highlight areas have only just started development and remain soft and fine-grained.  The resulting lith print is hard in the shadows and soft in the highlights, exhibiting colour effects caused by the fine division of the grain particles in the paper, so that the highlights appear tinted in shades of yellow, orange and brown.

The key to contrast and colour in developing a lith print is deciding when to snatch the print from the developer and stop the development of the shadows.  When the print is lifted from the developer the shadows stop developing almost immediately as the developer soltution in the paper is exhausted very quickly.  the highlights continue to develop until the process is stopped in the acid bath.  This makes the duplication of a print very difficult as the precise moment of snatching and stopping the print can lead to quite significant differences in tonal range and density.

This is a print that was developed for about 5.5 minutes and snatched and stopped as soon as the picture looked recognisable under the safe light.

Too soft





The next try was between 5.5 and 6 minutes, also snatched and stopped immediately - see how explosive the development is  - when it finally starts!

Too hard

Finally, I managed to get the tonal range I was looking for, only to find that I'd contaminated the paper with fixer from my gloves.  That's what caused the featureless finger prints all over the bottom right of the frame...

Just right - but I've broken it!



Now I've managed to get viewable results, I'll be much more confident at the next try.  I'll try a range of exposure times and then try pulling the prints early and late to see what colour effects I can get.