Tag Archives: half-plate

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)

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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 🙂

Progressing with Antique Photography

The next step in the experiments with the #antiquecamera was to try a contact positive print. First step the paper negative. Now I have established that I can trust the readings from the Lux App (iphone) – with ISO 6. I wanted at least a 4 s exposure as it minimises vibration effects from removing the lens cap. This gave an F stop of 32.half-plate-classical_bust_negative

To make the positive successully (Under red light) I wetted the papers before putting the negative face to face with the print paper. The negative was on top of the paper. I then illuminated the papers from 2 feet above with a flash from a flash-gun. Some experiments with different flash intensity was needed. – And success 🙂

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