Adjust Devlpt Time How Much?

[jeff glass]

Assuming I've done all film speed and maximum black print time tests correctly

 

Then, a Development time test, where I print a Zone VIII negative shot at proper speed, exposed in

enlarger for proper time, half of the print covered at exposure.

 

Result: no density visible on Zone VIII side compared to unexposed fixed-out paper white.

 

Assuming the conclusion is I need to shorten development (that is correct, right?) how much

should I adjust devlpt time down for the first re-try?

 

the guide I'm using says 1 minute, but shouldn't it be a percentage of your total development time

(which is 9:45 in D-76 1:1 at 68)?

 

Should I adjust down 20%? 10% 30%???

 

thanks for any help.

 

Jeff Glass

[leicaglow]

I think you're missing at least one variable, and maybe more. What film are you using, and what does Zone 1 and 2 look like now? If Tri-X, and large format, then 1 minute might be about right, but it might be a hair long too. Others will probably tell you that a densitometer is in order.

[chris_waller]

My approach is to reduce development time by 10 percent and then print again. If it's still too dense then reduce by a further 10 percent. This will probably be too much so then I split the difference and go for a 15 percent reduction from the original time.

[jeff glass]

Thanks for the responses.

 

Chris: well, it turns out that 10% is almost exactly 1 minute so I'll try that.

 

Michael: I'm using Tri-X 400, 135.