Optical density required to develop KF95 / KF152

Since you haven’t gotten any other replies, I’ll try to say something which hopefully will be helpful. You are right about 4.0 being good. I’m not sure how much lower you can go and still get a good plate. Remember, the transmission density scale is a logarithmic scale…..3.0 lets 10 times the amount of light through that 4.0 does, so it’s a big difference. Another crude way I have checked whether a negative is dense enough is to hold it up in the direction of a bare fluorescent light tube which is lighting the room. If I can see any image of the tube at all through the negative, it is not dense enough.

You could always make a test negative with the density you are thinking of using, and see how well it works when it is used to make a plate. Make a test negative with solids, lines of different thicknesses, and reverse lines of different thicknesses (reversed out of a solid), and any other image types you usually print and want to include. Expose plates with the test negative, for different times, and see if there is an exposure you can get acceptable results with.

Thanks Geoffrey for the advice :)

You’re welcome and I wish you success!