10x8 camera / printer.

[DaCh]

My 10x8 project has now reached the mk3 and I think this one will do the job nicely.
It has a curved film carrier; film is loaded through a removable door at one end.
It takes the picture and then can be used to make a contact print.
Two pinholes for taking: 0.5mm = f300 and 0.7mm = f214
Two much larger holes for printing, 2mm = f75, 3.5mm = f45
The shutter is a Cannon body cap that bayonets into a rear lens cap.
It comes apart to flat pack so it is easy to transport.
Why?
So I can take everything I need to make a negative and then produce a positive print without needing to leave the location. I can pack all the equipment and chemicals into a rucksack and two panniers, go camping and make pictures. All I need to find locally when I arrive is some water.
Early days yet, the camera is now sorted, it is light tight and has made its first negative and positive.
A few details to finish it and then I need to get out there.
The camera is loaded in a large changing bag, paper is developed in a Paterson multi 5 tank, which needs about 500ml and continuous agitation.
Attached files

[DaCh]

This is the inside of the front; the four pinholes are now sandwiched between two pieces of black plastic card. Hopefully the rest is fairly obvious.

Attached files

[DaCh]

The film loading door.

Attached files

[DaCh]

And here is the first test. Yes it’s the view from my back door again.
0.7mm pinhole. Multigrade not flashed, with pale yellow filter 12 minute exposure.
Contact print was without any filter, 3.5mm pinhole, camera pointing at the sky and double the incidence meter reading from the meter also pointing at the sky.
I still need to make the filter holder and also a translucent filter to ensure even light for contact printing.
Incase you were wondering this was toned in PS. Attached files

[JoeVanCleave]

David, this is a great design, wonderfully executed. I've not tried contact printing in the field in-camera, but have done preflashing with a thin piece of translucent white plastic placed over the lens, pointed upward at the sky.

I am curious about the details of the film holder slot, how the film stays put, and how you manage to keep the two layers in tight registration when contact printing.

Regarding processing film or paper in the field, this again has me inspired to return to my now several years old project of the portable darkroom box, perhaps with the Harman direct positive paper. Though I will admit that paper negatives are easier to get a good tonal range from, though they do require the additional contact printing and processing step.

Great job, looking forward to more images.

-Joe

[toniox]

This is why I love pinhole photography, sometimes so much ingeniosity for a primitive process ! I liike your design !

[renon]

Fantastic design. I like the idea of making contact copies directly in the camera very much.

[DaCh]

Joe
The film stays put because when the lid is closed there is very slight pressure on the end of the film.
the two sheets stay together for contact printing because they are curved, try holding two sheet of paper together and then curve them slightly, so simple it hurts!
The curve is only slight, the ends are 20mm further forward than the centre, it is enough to make the two sheets stick together but has no noticible affect on the image but it does even out the illumination. I was worried that the slight difference at the ends of a flat plane would be magnified when the same un-even illumination was used to print it.
And also I will use it to pre flash so that may make a contrast variation, I have no idea when all these things would start to show but the curve should solve that problem.
The film carrier is made from black plastic sheet and looks like a curved dark slide (without the sheath).
I forgot to mention that the rotating pinhole stage has a blank setting so I can take the lens cap off to change filters etc.
That is quite important.
My approach to the dark room is different to yours, the only thing I do in the dark (changing bag) is load and unload, every thing else is in daylight. This does have the disadvantage that I can only work to consistent times and there is no chance of inspection.
I have done in camera test strips but it is a bit tedious, three peices of thin black plastic between the two sheets, together the three peices make up to 10x8. Once they are in; one peice is removed (it is only used to position the others)
Make the first exposure then back in the bag and remove one peice etc.
It is guys like you Joe who started me on this idea and I had no idea how much fun it would be so thanks.
Next I think I may have to install a small steam engine to drive a flag waving machine that warns people when it is making an exposure ;D

[JoeVanCleave]

Thanks for the details, David. Your design is very ingenious, I may have to borrow some of your ideas!

Although it is very convenient to have a walk-in darkroom, I often work out of a changing bag or portable darkroom glove box, and also like to process the 4x5 sized paper in a Jobo bottle at the kitchen sink.

Looking forward to seeing more.

-Joe

[colray]

This camera is fantastic.

Just one question ..contact printing from paper negs are you stripping the back of the negative?

I have experimenting with paper negs and salt printing... but the exposure time is getting a tad on the long side.