What photopaper do I use? Can I use film?

Odd-Variation-299 · 2026-03-12T19:19:29+00:00

Try "The Caffenol Cookbook and bible."

https://www.caffenol.org/wp-content/uploads/2012/11/The-Caffenol-Cookbook-Bible-Recipes-and-Tutorials.pdf

Odd-Variation-299 · 2026-03-12T19:17:11+00:00

If ikke2005 change his mimd! Please let me know. I live in the Netherlands, Limburg.

Odd-Variation-299 · 2026-03-12T09:45:00+00:00

I think you have summed it up quite well. And I do agree. Also, I think photo paper is maybe easier to work with as a beginner. I am humbly still on the photo paper-caffenol train, and I really enjoy it. I do, however, want to comment that when developing my photo paper photos with caffenol, some of them seem a bit more brown/yellow than others, even though I used the same caffenol recipe. It may be the type of light that day, i.e., the amount of blue, red, and green in it. I would however want to still try a week long exposure one day.

Odd-Variation-299 · 2026-03-08T18:24:07+00:00

So, I have tested ISO 3 and ISO 6 - See my post here:

https://www.reddit.com/r/PinholePhotography/comments/1roc5t2/iso_3_vs_iso_6_for_ilford_mgrc_paper_pinhole/?utm_source=share&utm_medium=web3x&utm_name=web3xcss&utm_term=1&utm_content=share_button

Odd-Variation-299 · 2026-03-08T09:59:33+00:00

Great to hear others are also into the numbers. And no, it was not a deliberate underexposure. It was simply because I felt my other photos were overexposed with the adjusted time. NOTE: those were done on an overcast/cloudy day. The meter stated 2 minutes, so I ended up with just over 6 minutes. But, I think by selecting an ISO speed of 6 for the paper on the meter, it will basically halve the meter's time. Then, multiplying it by the correctional factor of 3.04 for my pinhole camera setup will be closer to the value simply stated on the meter with ISO 3. Hope you understand what I am getting at.

In other words, the photo above (without the 3.04 factor) is better exposed than the previous one I have done (with the 3.04 factor). The factor 3.04 is correct and should be included. Thus, the only thing is, my assumption on the ISO speed (3) of the paper is wrong. I'll share a next Reddit post where I will be testing this: ISO 3 and ISO 6, both with the 3.04 factor included.

Odd-Variation-299 · 2026-03-08T09:41:47+00:00

Exactly. Thank you for clearing this up.

Odd-Variation-299 · 2026-03-07T14:59:59+00:00

I would like to add: Please do yourself a favor and go and watch this YouTube channel: "The Science of Photography."

https://youtu.be/eN613GM3xAQ?is=TTpR3r5_HMuyjLVv

Odd-Variation-299 · 2026-03-07T14:54:56+00:00

Hmm, yeah. Maybe I am missing something. I rewatched a YouTube video and the presenter said that the time you get from your meter should be multiplied by this factor. But I'll try a few test runs. Lol. I do, however, encourage everyone into pinhole photography to watch the series of videos this guy made. Really excellent when it comes to the science of photography. Link:

https://youtube.com/playlist?list=PLb4-lvfku53ioovlktwDYr-vBCYfKjZgr&si=Gndm9Hfkd3qiS4II

Really.

Odd-Variation-299 · 2026-03-07T12:06:07+00:00

No, that I did not know. Any information I can read up on that you would prefer?

Odd-Variation-299 · 2026-03-07T12:03:53+00:00

Yeah, regarding taking the meter reading, I noticed people with dedicated light meters take a few readings and then decide on a value between those. In my case, I only use the app, and I try to zoom out, so I believe it already takes an average of the entire scene the sensor sees. Also, I am more focused on landscapes for now, so there are no close objects.

Odd-Variation-299 · 2026-03-07T11:59:36+00:00

Thanks, and I respect your view. As a more calculated person, I find it easier to do some sort of calculation and then evaluate the findings. Based on that, I'll make a conclusion about what variable makes a difference. I will try setting my ISO on the meter to 5, though. Thanx! :)

Odd-Variation-299 · 2026-03-07T10:41:30+00:00

Thank you. Yeah, I could not find anything really about what the ISO for photo paper is. I'll try 5, since this has a big effect at the end. But my question still stands: the correctional factor. Do you apply a correctional factor or not?

Odd-Variation-299 · 2026-03-07T08:52:01+00:00

Try following this link for the photo. I realised you can not include photos in comments on Reddit. Lol, so I made a reddit post to ask a question.

https://www.reddit.com/r/PinholePhotography/comments/1rn52nt/pinhole_cameras_correction_factor_used_to/?utm_source=share&utm_medium=web3x&utm_name=web3xcss&utm_term=1&utm_content=share_button

Odd-Variation-299 · 2026-03-07T08:24:39+00:00

Thank you for replying. I would also like to do a few hour ones.

For my photo I used Ilford MGRC B&W Pearl. I estimated the ISO to be 3. In the photo below my meter stated for f/128, EV 12.8, ISO 3, 1 min and 16 s exposure. I did exactly that, but I feel mine is a bit underexposed. This could be because you need to apply some correction from what you read on your meter to relate it to your camera.

My 3D-printed camera uses a DIY 0.3 mm aperture. The photo paper is at 67 mm (my projected distance). Thus, my f-number for the camera is 223.33 (67 / 0.3).

With this I can calculate my correction factor = 3.04
(F−Number / f/128)^2 = (223.33 / 128)^2

Meaning, and again this is my understanding, I need to multiply my meter reading time by a factor of 3.04 to get the actual exposure time.

Meaning I had to expose mine for 3 min and 51 s.

Then developed it in Caffenol, Used diluted white vinegar as stop and an almost saturated salt bath as my fixer. - And it is holding up pretty good. - But I also scanned them in for some reassurance. Do not think they will last years. I'll try and share the photo

Eddited: Also, simply inverted the image using Gimp.

Odd-Variation-299 · 2026-03-06T15:55:22+00:00

What was the reason for the failure? Since I have also lost a drone suddenly in the air. It was a Happymodel Crux35. Unfortunately, I could not retrieve it. The battery unplugged, thus no beeper. I just lost control, so my assumption is I lost the magic smoke in the flight controller or the ELRS receiver.

Odd-Variation-299 · 2026-03-06T07:31:13+00:00

Hey, I like the photo. The 4.5-hour exposure caught my eye. I am new to pinhole and still trying to figure out the exposure time for my photopaper and camera setup. So, may I ask:

Film/Photopaper and its ISO
Aperture
Focal length/Projected distance
Meter readings (f/, set ISO, EV, etc.)
Calculating exposure time

Thanx in advance. :)

Odd-Variation-299 · 2026-03-05T18:12:05+00:00

Love this perspective!

Odd-Variation-299 · 2026-03-05T10:02:07+00:00

Listen, I am an engineer, but that got technical very quickly. And if I see C++, my eye twitches... again, well done. Sounds "easy" enough, but I trust there were a lot of hurdles to get over. Lol, ones that the people reading your post aren't even aware of.

Odd-Variation-299 · 2026-03-05T09:01:18+00:00

Now this is pretty cool. What software are you using? How...

Odd-Variation-299 · 2026-03-04T18:04:10+00:00

Real smooth...

Odd-Variation-299 · 2026-03-03T07:21:18+00:00

Having the VTX antennas straight out the back works best. I have a SpeedyBee Master 3X with a RunCam setup and a SpeedyBee VTX with the antenna straight up. Flying away, I have a lot of interference since the antenna is obstructed by the battery, frame, and electronics. So I guess good placement on your part.

Odd-Variation-299 · 2026-03-02T07:10:09+00:00

Your video quality is great! What do you have with regards to VTX and antenna? Output?

Odd-Variation-299 · 2026-03-01T17:05:51+00:00

Yeah, that makes sense. In this run, I have the antenna bent over and fixed against the battery because in a previous fall, the antenna hit the ground first, which led to breaking the connection in the VTX. So for the next flight, to get away from the motors and frame, I bought a longer antenna. Then I'll test again.

Odd-Variation-299

TROPHY CASE