Efke 100 at 400 speed?

I have tried a bunch of films within the past two months and have found that I like Ilford Delta 400 and Efke 100. My question is: How can I, if possible, shoot Efke 100 at 400 speed? Will it produce the same sort of grain at the regular 100 speed? I am quite found of the efke grain but I have found it especially hard to shoot indoors with it. Anyone have any suggestions on how to shoot it at 400 and what would be the developing time for that? I usually develop in Ilfotec HC. Nothing too special.

Expose for the highlights and stand develop it in Rodinal 1:100 for 45 minutes as a start.

I would not recommend using Efke 100 at 400 in any developer. You will gain a lot of grain and lose a lot of shadow detail. If you just want grain then shoot HP-5+. You can develop it in Rodinal at 1:50 for a lot of grain, in undiluted Microphen for less grain and in undiluted D-76 for still finer grain.

Not as bad as it sounds EFKE used to state a speed of 250 ISO in FR E24 (similar to Microphen) for KB/R/PL 21 - now called KB100 so you're only pushing slightly.

EFKE films are quite unique as they are faster than box speed in Daylight, but box speed in tungsten lighting. In the UK they were sold at twice EFKE's speed by a major chain as their own brand films.

See below

Ian

I shot KB100 at 400 by accident while on exchange in Finland all of last year, and as a result I didn't touch the roll for a long while. I did develop it over thanksgiving break away from uni though, and found that Rodinal 1+50ish for like 16/17 minutes or so gave me some really great negatives with agitation every 30/45 seconds.

I've gotten very good results with Efke 100 4x5" in Acufine rated at 200, but I wouldn't go to 400.

I also think 400 is a stretch. I think if I did do it, I'd be inclined to expose for 200 or so and try a very compensating developer (e.g. POTA).

Then again, people should just experiment and try things, we might all learn something There are a lot of cantdos that have worked out well enough for me.