Max push of Delta100 sheet film

[m_p7]

I shot a couple sheets of 4x5 Delta100 in a pinhole camera. Metering

gave me 8 minutes at f/256. I doubled that for reciprocity as a

guess, but after looking at the reciprocity chart, I realized that

I'm probably still several stops underexposed. Anyone have some

suggestions for getting the most speed and a useful negative from

this? I was leaning toward DDX for 30 minutes (from

digitaltruth.com's 2.5x factor for a 3 stop push with comp. dev.),

but I also have Xtol, Rodinal, HC110, Ilford HC, Tmax, and Microphen

developers handy. Any suggestions appreciated. I'm more interested in

film speed at the expense of grain if that helps, since I won't

enlarge this much at all. TIA -Mike

[anupam]

Looking at the exposure table from the PinholeDesigner, your time looks about 10 stops underexposed. That would be quite a push. Haven't looked at the reciprocity chart for Delta 100, though.

[nige_buddy]

I must be missing some text in the 1st post.. nowhere does it say how much light was 'about' so how can you say it was "10 times underexposed" .

 

I have a f200 bodycap pinhole and it's documentation suggests 4secs at f240 for 100asa and when I've used it density has been fine. I was fine-tuning my 8x10 pinhole with paper negs today and with f288 I got good exposure for paper (asa of 4-6) of 2minutes (metered at 1/125 @ f16 for 400asa). So, it must have been a fair bit less than 'Sunny-16' to warrent 8min for 100asa or somethings a miss with your calcs.

[anupam]

<i>nowhere does it say how much light was 'about' so how can you say it was "10 times underexposed"</i>

<p>The post does say that the correct exposure was 8 mins @ f250 without reciprocity correction. You need no further information about the light, unless you are assuming that MP made a mistake in calculating exposure.

 

<p>Now if you look at the chart WITH the reciprocity factored in, you will see that 8 min is the equivalent of about 1/2 a sec. Well, its not exactly 10 stops but you can calculate the amount of underexposure from there.<p>-A

[m_p7]

Well, I finally got around to processing that stuff, and after I thought about it and looked at the pinhole designer program (thanks for that, BTW), it looks like I was about 5-6 stops under. Here are the results, hopefully you can read the text in the shot; I had to keep the size down so the pic would display in the thread.<div></div>

[m_p7]

Shots are from Muir Woods in California, BTW.