Pulled SFX 200

Hi,

I have just shoot Ilford SFX and found that I have left ISO set to 100. Usually I develop SFX according to Ilford ID-11 1+1 for 17 minutes. To my surprise there is nothing about SFX@100 at Ilford datasheet and very little at digitaltruth. I would shorten developing time to 13 minutes, any other idea. Or time for Perceptol? A bracket heavily when shooting SFX, yet I would like to have the best possible starting point.

I've used this film a bit but have not pulled it. Can you tell us a bit more about how it was exposed? Was it TTL metering and if so what filter was in place?