DX Coding for 35mm
It often occurs that film, especially negative film, stands to gain from slight overexposure. With 35mm SLRs it is an easy task to set the ISO exposure index to whatever you want. But with point and shoot cameras the exposure index is set based upon the series of black and silver 'blocks' on the canister of film. The only way to alter the exposure index that a point and shoot uses is to alter the 'blocks' on the film canister. This is a table of what those blocks mean and the different patterns for the different EIs and whatnot.
Looking at the film canister with the spool end jutting out to the left and the film tab to the top the two lines of blocks are arranged such that the top row indicates the designated ASA and the second row indicates the number of frames and the 'type' of film (whatever this means).
My method of getting these codes is to scrape the black paint off with a hobby knife as needed and then put cellophane tape over the regions that should be black. The code reader in cameras is based upon metal-to-metal contact of the sensors to the canister. Putting tape over areas that you want to be 'black' will achieve the same affect as using non-conductive black paint.
|Top Row (nearest to the film leader)|