I use xuan for printmaking and i hope to try it with cyanotypes. I'd be concerned that the paper might "transfer" dust or paper bits to the print? I find a squeegie works fine. One time out in the field i used the edge of one of the plastic magnetic print frames as a squeegie. it worked as well.

I appreciate that. I am also going to try taking a gray card with me, and take readings off of that, instead of the general scene I'm shooting. My thinking is, that the iPhone app I'm using is trying to adjust for the scene, but doesn't have a 'control point' (that's the best I can explain it) eg. I'f I'm shooting a bright wall the app may tend to under expose, whereas for a dark wall, it might over expose, since in both cases it's 'pushing' the exposure towards grey or a mid-tone. Again, I am new to analog so a great deal of the light stuff and the calcs - convering from f-16 ISO 100 to f-229 IS0 2 is a bit baffling for me.

Not really, but I haven't used the preflashing enough to know for sure.

I'm a newbie to film photography, so I'm wondering ... Are you suggesting that it's okay to use only developer and fixer if we're careful. For example: That we try to remove as much developer as possible for the camera; that we don't use spent or exhausted fixer, etc? Best, David

Thanks. Any suggestions on bulb type / power? B&H photo has a number of bulbs that seem 'old school' (incandescent) with different wattages. Also, the hardware store sells 'full spectrum' LEDs that are labeled 'grow lights' which I think might work? And ... I already own a small Speedball UV light for cyanotypes AND a much larger and much more more powerful NuArc exposure unit (made originally for the offset printing industry) - I believe it has a metal halide bulb, and I have used it for exposing polymer gravure plates. Do you think any of these might - or will - work? Best, David

Do you use the 'diffuser lens' (which is used to pre-flash direct positive paper), or just the 'regular' pinhole. Also, I already purchase the magnetic contact print frame from Pinstra. I assume that one advantage is that it will allow me to have more control, and maybe shorten the exposure time needed, but it's all new to me ....

(Here in US) I bought a NEBO Mini Larry 500 (lumen) flashlight. It's only 11 cm (4.25 inches) long, so it fits in my bag. It has a rechargeable battery and comes with a USB charging cable. I know that Martin recommends a 1000 lm. torch, but I found that my 500 lm. Mini Larry works well, using the same pre-flash exposure times. I also have a much larger Best, David

Thanks again for your response. Please see my latest post, below. As I understand it, to get from a 'proper' exposure at f/16, ISO 100 with my Lumix to f/229, ISO 2-3 with my Pinstra, I need to take whatever the Lumix exposure time is and ... Multiply it by (229/16) x 50 or 716 ... but as I said, that seems way off. If you have a better number to work with, I'd like to know it. Perhaps you're suggesting that I used 256 (f-stop conversion) x 50 (ISO conversion) which means I'd multiply my Lumix exp time times 12,800? [Based on this, if I had a half second exposure with the Lumix this would translate to a 1.75 hour exposure with my Pinstra.] Your long explanation and all the calcs are fine, but since I don't know 'analog' photography at all, much of what you shared I'm not able to follow. Best, David

Thanks, I appreciate your response, though I am confused by it. Here's how I'm calculating the conversion from Lumix to pinhole exposure, based in part on my understanding of what you said: Based on my Lumix settings of f/16, ISO 100: from another webpage www.pinhole.cz/en/pinholecameras/exposure_01.htm ... to get the correct f/stop calculation number. divide: f/229 / byf/16 equals 14.3125, then multiply by 50 to add in "proper" ISO conversion (as I understand your response above): So now I have 14.3125 x 50 = 716 (rounded from 715.625) ... so, Based on a 5 sec exposure (with my Lumix), this is giving me a 'proper' pinhole exposure of 3,580 seconds, or about a 1 hour exposure. However, based on my Pinhole Assist app my expose should be 3.5 to 4 hours! Something seems amiss, which might entirely be me and my calculations and mis-understanding. Best, David

Thanks. If you are using tracing paper won't it interfere or partially block the image -.at least where the paper is located?

Thanks. That is VERY HELPFUL. I was traveling - and plan to travel again - with photo paper, not film. I emailed Ilford to ask if the same guidelines apply for photo paper as they do for film? If so, this might explain why almost all of my images failed: I checked them in my luggage for at least one of my travel directions, so they were exposed to the more powerful x-rays that Ilford recommends against. If they have any additional info for photo papers, I'll be sure to share here. Best, D.

Sorry if I wasn't clear concerning what I was asking about. Do you have any tips, cautions, etc. about traveling with exposed and unexposed photo paper, especially by air?

I hope Jon doesn't mind if I expand this a bit, but I'm wondering about using Liquid Light in general as a way to create my own photo paper? Best, David

Tim, I'm not asking about my exposure times or how I'm developing my prints or the condition or dilution of my chemicals. I'm specifically asking about what could negatively affect my prints or the photo paper when I'm travelling - especially by air. Now that I have been playing with the Pinstra for a few months, I'm getting more consistent results - and if they are 'off' I generally know or can guess at the reason.

Okay, I'll have to take some time to absorb all that. Basically, I look at where they middle of the camera is - and then consider the upper half for one exposure and the lower have for the other exposure, each time covering up the part that's not being exposed at that time. I am almost always shooting in portrait mode. I did this with some success with a still life set up, but I didn't quite get the placement correct. But the idea generally works, I just need to practice it. I am mainly concerned with the exposure and how not to either under or over expose when I'm taking two images on one piece of photo paper. You're ND filter info helps with that.

Wow! That's a bit more detailed for my pee brain to comprehend all at once, but thanks. I'm looking at one or a set of Conkin p-size graduated ND filters and just hand holding them, at least for now.

Thanks! Can you give me a few specifics? What size filter, how many stops, hard or soft edge, etc? I have been using a black / dark sheet of paper to block out half of the image at a time, but a graduated filter would be better. And yes, there is some creative play in how they are exposed.

Yes, there is always room for experimentation and thinking outside the exposure, but you are saying that in general mine is a good starting off point I've also been trying to cover up one half of the image, then moving the camera and covering up the other half, with the idea that I can give each a more full exposure, since the 'other' side is being covered as if it's not being exposed at all. I've had interesting but mixed results so far.

Thanks Tim. A few follow up questions: Is this calculation for Harman Direct Positive Paper? I ask because I know that using 'normal' photo paper has a much, much short exposure time. And, does the ISO setting affect your calcs? I assume the f/16 time would be at 100 ISO, correct? Thanks. David

Thanks. My neighbor also said it was from underdevelopment, and it's the edges of the paper that are secured under the camera's lip. I can live with it, if it's no issue otherwise, Or, fix for longer, or I've also been developing some of my prints out of the camera and there are no colored edges. Best, D.