A bit of back to basics

[Grandpa Ron]

So far I have only had a bright but overcast day to shoot, no distinct shadows. The light meter indicated f22 at 1/10 sec. so,

• I shot two sheets at that f22 for 1/10 sec. I will use these to test the developer time. I will do one at the recommended development time and one a 1 1/2 the recommended time.
• I also shot one sheet at f16 for 1/10 sec. or one stop over.

A few minutes later, the it was a bit brighter and the light meter indicated f22 at 1/25 sec. so,

• I took one shot at f16 or 1 stop over the meter reading.
• and one shot at f 11 or two stops over.

Because the 4x5 camera lens is 123mm I use a small aperture to get a decent depth of field.

Tomorrow is Pinhole camera day 4/26/20 so I will shoot a couple of more sheets, that will give me enough film to mix up a batch developer.

Rodinal has been around for a long time, so my intuition tells me that the problem is with my lens exposure and/or the light meter, rather than the published development times.

I will post my result when I am finished. Thanks again for the suggestions.

 

[dxqcanada]

Eh, I just thought of something ... how much exposure do you lose if the sheet film is loaded backwards in the holder?

Was looking at the Iford datasheet for FP4 sheet film, and states it has an anti-halation backing ... so if put in the holder the wrong way you will lose (not sure how many stops) exposure. I've done this back when I first was learning large format, didn't remember which side the notches should be when loading (notches on the right is right!!)

 

[Grandpa Ron]

Examining the basics. I will skip the boring, time consuming details.

My light meter is a selenium cell of unknown viewing angle. But, by comparing it's reading to those of my DSLR and an old film camera meters, on the sky, a brick wall and other such objects, I find they are all within about +/- a half a stop of one another. So no major errors there.

Next I shot a series of pictures at the same f stop for testing deferent development times. With 50:1 Rodinol, they were developed at 7 minutes, 10 minutes (recommended) and 14 minutes. All three development times produced usable negatives over about a two f stop range.


The distances from the safe light to the enlarger easel and to the developer tray are both over the recommended three feet, but he safelight is mounted against a mirror, so I changed from a 15 watt to a 7 ½ watt bulb, both are incandescent bulbs.

My final issue was with the short enlarger time. A typical enlarger print time is about 4 sec. I had replaced the 150 watt incandescent bulb with a 60 watt equiv. LED bulb. Comparing the two, the incandescent bulb was a warmer light yellow color while the LED, marked 1600 lumens @ 5000K, was a colder bright white.


I assumed the LED was rich in the blue spectrum, so, I added a pale yel./grn. filter gel sheet between the bulb and the negative tray. That doubled the enlarger exposure time. To the eye the yel./grn. filtered light seems about as bright but the grade 2 and grade 3 photo paper is sensitive to the blue. I was going to add a second filter sheet but by that time, I had already burned through enough paper and time.

Putting what I had learned to the test I used my last piece of cut film to shoot, develop and print my travel trailer as shown below. Though it does not scan well, the print looks good on grade 3 paper.



The point of this month long exercise was not to find the “magic formula” for a perfect print every time. The intent is to better understand the equipment and techniques I have at my disposal to produce a decent print, from which to quote Ansel Adams, “A fine print can be made”


Again I want to thank every one for their input.