Developing pinholes

[jwhit]

Hey all. I was making a pinhole camera project at work and kept getting back uncool results http://oi40.tinypic.com/fz3wbo.jpg (sorry, i was mobile ). I only had highschool photo (2yr), and I can't remember how I did my pinhole assignment all those years ago. Needless to say, this current craft is kicking my butt. I'm running out of self-reliance, and if anyone can enlighten me that would be great


Here is the camera I've narrowed down to (after trying boxes of all sorts): http://oi41.tinypic.com/wl29w8.jpg. This pinhole was actually made with a paper clip; I got frustrated and the work day was almost ending so I was still testing. I used a proper needle for the first boxes.


The black pictures were exposed for ~2mins. The lighter ones at 5-15secs. The lightest one at the bottom was my test to see if my paper was bad.



I am using a brewed developer of 8oz water, 2 tsp instant coffee crystals, 4 tsp washing soda. I also tried 8000mg of vit c, but then I threw that developer out when I kept getting pitch black returns.


Stop bath of water:vinegar 4:1


Fixer is Kodak, all directions followed.



Anyone? Thanks!

 

[Derrel]

First off, I would not use coffee-based developer. Get some "real" developer, from Kodak, or Ilford.

 

[Josh66]

Yeah, I don't think I'd be using 'caffenol' for best results.

If you really just want to make your own developer, pick up a copy of The Darkroom Cookbook, by Steve Anchell (I believe the third edition is the latest). It's good reading even if you don't plan on making your own chemicals from scratch.


It's hard to really see anything in the picture of your prints, but in the picture of your pinhole camera - what is the material that the pinhole is in? It looks like aluminum foil or something. If it is, that may be the source of your problems. For one, unless you've painted the inside - it's reflective. Secondly, punching a hole in foil with a paper clip is going to make a hole way bigger than the paper clip. Your 'pinhole' may only be around f/45 or f/90. (I'm thinking that can has a focal length of around 80-100mm, a paper clip is probably pretty close to 1mm - so your aperture is probably 1.5-2mm...)

I've made similar pinhole cameras, but used aluminum from a drink can instead, and used a needle to make the hole (don't poke the needle all the way through). Spray paint the back side of the aluminum flat black before you put it on the box (probably not entirely necessary, but it can't hurt).

So, to summarize - like Derrel said, use some real developer; and your pinhole is probably way too big.


EDIT
Just realized that I have a (18oz) can of oatmeal in the pantry. I measured it, and if your can is the same size, the focal length is 100mm (maybe like 95mm since your foil is caved in a little).

 

[jwhit]

Yeah, I don't think I'd be using 'caffenol' for best results.

If you really just want to make your own developer, pick up a copy of The Darkroom Cookbook, by Steve Anchell (I believe the third edition is the latest). It's good reading even if you don't plan on making your own chemicals from scratch.


It's hard to really see anything in the picture of your prints, but in the picture of your pinhole camera - what is the material that the pinhole is in? It looks like aluminum foil or something. If it is, that may be the source of your problems. For one, unless you've painted the inside - it's reflective. Secondly, punching a hole in foil with a paper clip is going to make a hole way bigger than the paper clip. Your 'pinhole' may only be around f/45 or f/90. (I'm thinking that can has a focal length of around 80-100mm, a paper clip is probably pretty close to 1mm - so your aperture is probably 1.5-2mm...)

I've made similar pinhole cameras, but used aluminum from a drink can instead, and used a needle to make the hole (don't poke the needle all the way through). Spray paint the back side of the aluminum flat black before you put it on the box (probably not entirely necessary, but it can't hurt).

So, to summarize - like Derrel said, use some real developer; and your pinhole is probably way too big.


EDIT
Just realized that I have a (18oz) can of oatmeal in the pantry. I measured it, and if your can is the same size, the focal length is 100mm (maybe like 95mm since your foil is caved in a little).

Thank you for the haste

I would have used a proper developer had it not been for the nature of the project; I work with kids and we like to try a DIY approach, if possible. We take regular trips to the store in order to stock up on site supplies etc, and so that's where all the coffee stuff came from. I was actually surprised it worked. That being said, we forgot to pick up the sodium thiosulfide(?) from the pool department, so on our way back to site we stopped into a photo shop to pick up the fixer and of course photo paper because we are all lazy. Then I just googled my way into the rest.

It is aluminum foil, and the 'inside' is not painted. Can't believe I missed that. Do you think I can permanent marker it? Tomorrow I will have access to a soda pop can, if that would work out better. Also, I knew the paper clip was a long shot...but I did not know the needle didn't need to go all the way through, either. I'll try it tomorrow.

On a side note, should I be mixing the liquids in darkroom (aka supply closet with a red-bulb lamp) or can I do it in the light?
Do temperatures matter as much as I think they do, or would I be fine with water-fountain water (very cold).
Also, what exposure times should I be looking for in an indoor setting? I can move outside if need be.
I can probably manage the developing times, but if anything I said indicates my obvious inability to do so through trial-and-error, ballpark times would be appreciated if available.

Finally, I am very sorry, but numbers don't mean much to me Like I said, my experience is incredibly amateur, and high school was so very long ago. Thank you for any hard work. I admire how exact you and other photographers are.

 

[Josh66]

The chemicals don't need to be stored in the dark, though it wouldn't hurt. A brown bottle is fine.

The smaller the hole is, the more exposure you'll need. Also the smaller it is, the sharper the photo will be. With film, if you knew the size of the aperture and the focal length (distance from the hole to the film), you could come up with a good starting exposure time by extrapolating from the sunny 16 rule. I don't know what ISO you would need to use for the paper though.

The focal length divided by the aperture is the f number. Pinholes are usually like f/180 or more.

The aluminum from a can works better because it is easier to keep the hole smaller.

The sensitivity of the paper and the size of the aperture will be the factors in coming up with an exposure time. I do pinhole with film instead of paper, so I don't really know how sensitive that paper is...

2 or 3 test sheets should get you pretty close though.

Until you're consistently getting good results, I would use a 'proper' developer though. Throwing developers that may or may not work as advertised into the mix just makes for too many variables to really know where it went wrong.

 

[Josh66]

Chemical temperatures should be roughly room temperature (68°F/20°C). Too cold will take longer, too warm will be faster.
24°C is probably about the practical limit - I get noticeably bad results above that.

 

[Josh66]

Also, if you're using the white lid that comes with the oatmeal, that is probably letting light in to. You'll want to paint that black too, or do something to make sure light can't pass through it.

 

[vintagesnaps]

Since oatmeal containers changed from having cardboard twist-off tops to clear plastic lids, there are some cardboard pinhole cameras being manufactured as well as cameras that are basically cans w/lids that advance film (I have one; it works). Pinhole Blender

There are plenty of resources on pinhole photography here - AlternativePhotography.com . You might be able to find instructions on making your own, how to determine exposure times etc. If you have the film processed by a lab you can ask for it to be developed only and have them leave the film in one long roll (don't have them cut it into strips, they should be able to put it in a sleeve and roll it up).

You might find some info. here too. F295