Tag Archives: #halfplate

Sheet film experiments

I now have some 7″x5″ sheet film for the antique Thornton Pickard (Boots) bellows camera. Unfortunately the film/plate holders are slightly less than 7″x5″ so in complete darkness, using masking tape stuck to the bed of the guillotine as guides, I trimmed down the film to fit. What you see here is my third day’s experiments – Day one produced under-exposed images, day two over-exposed and today – just right (mostly).  Setting up the still life by the kitchen window, I took light readings off each piece of fruit and the black paper backgroud – yielding recommended exposure times ranging from 4 to 30s at F32. As the 30s was for the black background I went for a 20s exposure and was very happy with the result. I used the same settings for my portrait shot.

Contact prints were made, experimenting with exposure here too. I am exposing using a flashgun held 45cm above the paper. The flashgun has a controllable intensity. – level 4 seems optimum – but doesn’t give quite the contrast I hoped for – I have ordered some filters on ebay to make the flashgun light more magenta as I have read this increases contrast – we’ll find out when they arrive.

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Optimum exposure for the film and print
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Under-exposed print (flash setting 3)
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Over-exposed print (flash setting 5)

Thornton-Pickard-resized-4070

One problem was the film/plate holders are old and fragile and some wood splintered off – the pieces that make them light-tight. So I had to make (using some mahogany veneer) replacement pieces.

The other problem I have encountered with these film holders is that the metal plates that sit in the middle separating the two pieces of film have springy pieces in the middle and these scratch the film and they don’t fit too well either. I am replacing these with stiff black paper and we’ll see how they perform.

My Day two efforts were outside – around Glastonbury – Godney. The light was too bright and I had to deal with exposure times of only half a second with this ISO 200 film even on F64. It wasn’t possible to accurately judge taking off and replacing the lens cap in these circumstances – though I did try. I have sourced on Ebay a shutter mechanism that will fit on the front of the lens allowing me to make theses shorter exposure times. Something to play with over Christmas 🙂

100 year-old camera’s photo of my garden

So, using the recently acquired “plate holders” to hold the photographic paper in the back of my, now modified, Boots Half Plate Mahogany camera, I have taken and processed some successful pictures.

Boots half plate camera
Boots half plate camera

Taking the exposure using my iphone and the “Lux” app and judging the ISO of the paper to be 25, I made 3 exposures of the paper at f32 for 4s (as Lux indicated) and also, 8 and 16 seconds. As 8 seconds was the most successful. Seeing as the app had suggested 4s as the correct exposure, I will assume now the ISO equivalent of the paper is 50 and work on that basis for the next tests.

I developed the paper and got three well focussed images with a full tonal range.

The images produced are of course negative images. These I then scanned in to the computer and through photoshop inverted the tonal range to give the black and white image you see here.

HalfPlate-photo-Garden1

The dynamic range is too great and I understand “flashing” the paper before use can help reduce this. That’s the next experiment.