Determine developing time for any film

[Ari]

Lately I've been trying out some new films, most in 35mm, and I need to get some developing times down but I wanted to see if I could avoid the tedious shooting/bracketing/developing/N-1/N+1 business.
I searched for a quick and dirty way to get a starting developing time, and found this:



(Fast forward because he takes a while to make his point).

I also found a recent post by forum member Neal that offered a not dissimilar approach: https://www.largeformatphotography.i...33#post1597433

What do you all think?
I've tried both methods and had mostly solid, consistent results. One or two outliers threw me off, but I just kept repeating the tests to have a larger sample size.
So far, I haven't applied the "data" to developing a roll of film yet, but I will very soon.

[Jim Noel]

The tests are worthless until you try them on a sample film you have exposed.

[Ari]

I just developed a roll of 12 shots, it looks good. I based everything on the test shown in the video above: time, temperature and dilution.
It's a very good starting point, from what I can see.

But I wanted to ask if there's any actual truth to this method or is it bunk?
In my case it worked, but maybe I got lucky.

[ic-racer]

I compare the slope of the first 11 points after 0.1 log d to a 'known' film for which I already have a development time for most scenes. Then tweak the development time as needed for the unknown film.

https://www.largeformatphotography.i...-100-Film-Test

[Neal Chaves]

Many people new to exposure and development testing don't have a good idea of what an excellent negative looks like. One way to approach this is to use Diafine for one's first development trials. With Diafine, the only variable is the rating of the film speed and this can be easily determined by making a proper contact proof of a roll of bracketed exposures. The makers of Diafine claim an HP5+ speed of 1600. At that speed, the negative will be thin and flat, but print pretty well on a N0.4 paper. For the best print quality on a No.2 paper, I rate HP5+ in Diafine at 400.

[LabRat]

For 35mm, you have a built-in test strip for determining developing time...

If you process a roll, there is the bit of the leader end on the front of the roll that gets processed that was fogged to light while loading the camera... This will develop to the d-max with the rest of the normal exposed roll... If you snip off after processing and examine, you can see how much the density developed... If super black and not transparent at all, too much, but if grayish (not fully black), too little... It should be black with a very slight transparency, so if you held the strip up to a light and put your finger in front of strip, you would see a slight shadow there...

Some used to put strip over a white printed page and see if the type on the page is slightly visible through strip, but just using a light works too...

To "extend" the range of a neg, one would slightly overexpose the box speed of film, and slightly underdevelop film for more transparency in the upper highlights, but still have good shadow detail... (A ratio of about 1/3 to 1/2 a stop overexposure and underdeveloped about 10% of time usually works well...)

Steve K