Do you Know the 25% Rule for Printing and Scanning?

Today's video covers what's sometimes called the 25% rule. This 'rule' was possibly promulgated by Kodak. It states that a 25% change in development time changes the print paper grade by 1. If you are constantly printing at grade 4 then an increase in development time by 25% will reduce your printing grade to 3. If you are consistently printing at grade 1 then a decrease in development time by 25% will change your printing to grade 2.
This is an important rule to know if you print or scan negatives. It optimises the development of your negatives and increases the quality of your photographic work.
Thanks for watching! If you like these videos why not become a Patreon of Pictorial Planet? Your patronage will support the making of these videos, my information website, and the writing of my second book full of photographic goodness.
John Finch
Pictorial Planet
Website: www.pictorialplanet.com
Patreon: / johnfinch
My Book: www.pictorialplanet.com/Book/b...

[@AI-Hallucination]

Going to have to buy your book thanks again man you a legend I have learnt more of you than I did in my HND 😂

[@user-qm8sx8ne8g]

A tip I hadn't heard of so extremely useful. Even better when you see its worth being proved in a print

[@PictorialPlanet]

Thanks!

[@stephendeakin2714]

Excellent tip John, thanks and thanks Kodak

[@AndrewHenderson]

Another great tip John, thanks again.

[@PictorialPlanet]

Thanks, Andrew!

[@kaibell7429]

super helpful video! just developed a couple rolls the other night and came out way overcooked. good to know for next time, thanks for all the informative darkroom and film videos too, your channel is a goldmine!

[@PictorialPlanet]

Thank you!

[@carstennorwaynorge2195]

Hei John, thank you for this nice video. Csn i use this rule for stand development on the same way? Wishes from 🇳🇴

[@PictorialPlanet]

Sorry but it won't work well with stand. With semi-stand it works fairly well.

[@carstennorwaynorge2195]

@@PictorialPlanet ok thank you👍🏻 have a nice weekend

[@shervinsardari]

Great tip, thank you! Bonus question: In case I have a very flat negative and I'm already at grade 5, could I overexpose the photo paper and reduce the development time in the dev bath in order to increase the contrast?

[@PictorialPlanet]

Watch my Printing the negative 2 and 3 videos

[@filmlovephotography]

Hello John, this can also be applied to pushing film? Thanks 🙏

[@eliyag1]

Increasing/decreasing development is essentially pushing/pulling film. When you push film by one stop you then develop it for 25% longer.

[@filmlovephotography]

@@eliyag1 I understand what you mean, but shooting at box speed and cutting 25% of developing time I see more like underdeveloping the film, different than overexposed the film in camera and compensate in the developing by cutting the time. But maybe is the same thing and I'm just confusing.

[@GaboDelgado1]

Same doubt here, for example, lets say you figured out that for a given film you have to develop for 25% less to get in the 2 1/2 as mentioned by John. Then you have a roll that you intend of pulling by 2 stops. Does that mean you have to develop 75% less time?

[@filmlovephotography]

@@GaboDelgado1 for what I understand developing is not linear, shadows develop slowly then highlights. So if you cute the developing time your highlights will be less white and because you pull the film by 2 stop, you overexposed the film. So your shadows are in zone 5 instead zone 3. But by cutting the developing time you put the shadows from zone 5 to zone 3 in the developing process. And you get more dynamic range by doing that.

[@filmlovephotography]

@@GaboDelgado1 but maybe John can make a video explaining all this in a better way 🙏

[@waltergaier9165]

Sorry… I don’t get it. Once my film is developed, how can I then decide to under- or overdevelop the same film?
Doesn’t the development time depend on whether I push or pull my film?
Or do you mean the development time of the paper?

[@patrick.hudepohl]

Film development time determines contrast in the negatives. Longer development means more contrasty negatives (and thus a lower grade filter when printing). Shorter development time reduces contrast (and you'd need a higher grade filter for a nice print). You can use this to your advantage: if you have taken pictures in very dull conditions and don''t want flat negatives, develop a little longer. If you were shooting in very high contrast (e.g., sunny day around noon) and want to reduce that a bit, develop shorter.
And yes, you also adjust film development time when pushing or pulling your film. With the same consequences for its contrast.