Help request for a scientific experiments for kids

Hi everybody
I'm a chemist and in my free time I volunteer in a scientific association. For the Christmas holidays I would like to organize an experience for elementary school children (6-10 years) on photography. They should build a pinhole camera (I found several tutorials on YouTube) and develop the photos obtained with the coffee method. I'm not a photography expert at all, so I'm going to ask you for some advice:
- can I use photographic paper or are photographic films better?
- how long should I leave the pinhole camera exposed to the sun?
- is the solution for development just coffee + soda or do I need vitamin C too?
- for the fixing, can I prepare a solution at home (I read something about bisulphite and thiosulphate)?
Sorry for all these questions (and for my poor english) but on the net I can not find a precise protocol.
Thanks in advance for the help!!!

You'll get better answers than this.
You'll need a darkroom.
If you use film, you'll have to print it - an extra step. However Harman sells direct positive paper.
I don't know if Caffenol is a suitable developer for the paper.
You can mix your own fixer, or use packaged commercial fixer.
Your English is just fine.

This thread might be of interest too:
https://www.photrio.com/forum/threads/edible-film-developers.33501/

"Can I use photographic paper or are photographic films better?"

Basically you can use both.
Film typically is much more sensitive, and typically sensitive to the whole visible spectrum.
In direct use film yields a transparent image, whereas paper yields a reflective image.
In larger format paper is typically much cheaper than film.

I would strongly recommend using photographic paper as the "negative". Film is much more sensitive to light so would require short shutter speeds that might be difficult to manage. RC paper dries more quickly and flatter so can be contact-printed onto another sheet of paper sooner than fiber paper would allow. Watch out for papers that have printing on the back. Back when I was playing with pinholes I used Ilford RC paper with success. The contrast will be high in outdoor situations that have a lot of blue light, if that's a problem you could tape a mild yellow gel over the pinhole to block some of the blue.

I've done this in the past with 4-H summer art programs. I recommend RC paper, it allows the kids to load the camera and then see the images develop in the darkroom under safelight conditions. Film must be handled in total darkness. I never used coffee based developer, only dilute Dektol (or similar) and disposable gloves for the kids worked best. i also used citric acid stop for no-odor, and alkaline fixer to reduce wash time.

Thanks to everyone
I found this on amazon: Ilford Multigrade IV RC Deluxe, it could be ok?

For film and paper you better look at a few major online photo supplies dealers devoted to film and paper.

Italy:
ars-imago.com

Germany
fotoimpex.de
macodirekt.de

to name just a few

Maybe do cyanotypes? The original formula with potassium bromide with ammonium ferric citrate is low toxicity and kids expose it in the sun. Develop in plain water.

I've developed paper negatives with just coffee + soda ( sodium carbonate ), and it's a little tricky. I suspect it would work much better with vitamin C ( ascorbic acid ) added, but haven't tried it so can't say. I think you should see if ECO PRO paper developer is available in Italy. Paper negatives in a pinhole camera is great fun and can produce quite amazing results!

In Europe available are several developers that are based on Pyrazolidone instead of Hydrochinon. For instance made by Adox, Moersch, Spur.

you can do it with caffenol, like nedL suggested caffenol C might work better
( i process paper in caffenol often ) .. yours sounds like a fun project !

betina89 said:

Hi everybody
I'm a chemist and in my free time I volunteer in a scientific association. For the Christmas holidays I would like to organize an experience for elementary school children (6-10 years) on photography. They should build a pinhole camera (I found several tutorials on YouTube) and develop the photos obtained with the coffee method. I'm not a photography expert at all, so I'm going to ask you for some advice:
- can I use photographic paper or are photographic films better?
- how long should I leave the pinhole camera exposed to the sun?
- is the solution for development just coffee + soda or do I need vitamin C too?
- for the fixing, can I prepare a solution at home (I read something about bisulphite and thiosulphate)?
Sorry for all these questions (and for my poor english) but on the net I can not find a precise protocol.
Thanks in advance for the help!!!

Click to expand...

Betina,great project, using PE paper is just fine and a lot easier than film.Yes you can mix sodium or potassium thiosulfate at home; ask here for a formula if you need one. treat the paper as having a sensitivity of ISO 3 to determine the exposure. best of luck and tons of fun!

I'll second Mainecoonmaniac. You could try Sunprints/cyanotypes. This would not work well in a camera, but could make the printing part easier for the kids, at least at first. You could do photograms with it, or just bring in some negatives they could print in the sun, and eventually get them to expose film or paper in a simple pinhole camera.

Harman direct positive paper is only available in fiber based. The washing time might exceed the childrens patience. No idea how flat it dries. Also, it costs more. 25 x 4"x5" HDP = £19.98. 25 x 8"x10" MGIV = £16.50.

With RC paper in a pinhole camera, they get to see what a negative image looks like. That can be digitally photographed and the image inverted.

Or re-photographed and by this inverted into a positive.

http://users.rcn.com/stewoody/photo.htm
This got me going years ago when I put together a pinhole club for middle school students.
You will need a few things but ultimately very easy to do and manage.

Ken

betina89 said:

Hi everybody
I'm a chemist and in my free time I volunteer in a scientific association. For the Christmas holidays I would like to organize an experience for elementary school children (6-10 years) on photography. They should build a pinhole camera (I found several tutorials on YouTube) and develop the photos obtained with the coffee method. I'm not a photography expert at all, so I'm going to ask you for some advice:
- can I use photographic paper or are photographic films better?

Click to expand...

As suggested, paper allows you to work under red or amber light (red leds work quite nicely). Keep in mind that your pinhole photographs will be negatives (white = black and black = white); to get a recognizable color print, you will have to (contact) print the negatives you make in the pinhole camera. Contact printing can be done as explained by others by putting a (paper) negative onto an unexposed sheet of paper, lay a piece of heavy glass on top of it, then expose it to the light of e.g. a bare white light bulb for a brief time (a few seconds will probably do with a low wattage bulb) and then develop the print.

- how long should I leave the pinhole camera exposed to the sun?

Click to expand...

Depends on the material used (paper/film), the size of the pinhole and the amount of light. With paper under sunny conditions, try something like a minute and adjust based on your initial results.

- is the solution for development just coffee + soda or do I need vitamin C too?

Click to expand...

The vitamin C will make the developer more active, which could be a good idea if you're working with inherently impatient kids. You can get vitamin C powder in online stores and some local drugstores. Keep in mind that the coffee/soda/vitamin C brew will be rather smelly (but not dangerous).

- for the fixing, can I prepare a solution at home (I read something about bisulphite and thiosulphate)?

Click to expand...

You can fix paper and film in a solution of sodium or ammonium thiosulfate, but really, it makes more sense to just get a bottle of rapid fixer (any brand will do) and follow the instructions on the bottle. Two things to keep in mind when handling fixer:
* The fixer contains acetic acid, so make sure the kids don't get it in their eyes.
* When the fixer is used, it also contains soluble silver salts, which are inherently toxic. Make sure the kids don't get it into their mouths (via their hands etc.)

Sorry for all these questions (and for my poor english) but on the net I can not find a precise protocol.
Thanks in advance for the help!!![/QUOTE]

Mainecoonmaniac said:

Maybe do cyanotypes? The original formula with potassium bromide with ammonium ferric citrate is low toxicity and kids expose it in the sun. Develop in plain water.

Click to expand...

Cyanotypes are nice, but you do need a negative or a template (for photograms); even printing leaves or household objects can be fun. Btw, cyanotype chemistry does not involve potassium bromide. The constituents of the classic version are potassium ferricyanide and ammonium iron citrate. The toxicity is indeed low, but the same common sense applies as with any photographic process: make sure kids don't get it onto their hands and then stick their thumbs into their mouths or whathaveyou.

Sounds like a fun project; I would start by just giving it a go on your own to set up an experiment that works consistently and reliably. The principle is straightforward; getting an experiment set up that is sufficiently flexible and robust to do together with kids is of course another matter.

Cyanotypes are nice, but you do need a negative or a template (for photograms); even printing leaves or household objects can be fun. Btw, cyanotype chemistry does not involve potassium bromide.

Click to expand...

You're correct! jnanian informed me of that. It's been a while since I mixed up a batch. I mixed up 250mls over a year ago and I'm working to use it up.