I have been trying my hand at salt prints recently thinking I was doing OK except that High lights were not being attained. To cut a very long story short I am now trying to eliminate fog/stain on the paper. I make 4 x 1 1/2 inch square pieces of paper which are coated with a 1 inch strip of sensitiser. Without giving any UV exposure they are immediately rinsed and then fixed in hypo. After washing they are air dried and within 3 -4 hours the sensitised strip begins to show a tone which increases in density over the next hours and days. This suggests to me that it is caused by insufficient fixing, but of course it may be many other things. This is my procedure 1) 2 pieces of paper are coated in a darkened room. I have no darkroom but use a darkened bathroom with the door slightly open to give me just enough light to see. 2) The paper is then dried for 30 seconds with a hair dryer on low. 3) the paper is then rinsed in tap water for 2-3 minutes. In the very low light I cannot see when the 'milkiness' clears but 2-3 minutes seemed right when I used brighter light. 4) the samples are then immediately put into a 10% solution of hypo and given continuous agitation for 3 minutes. At this point 1 piece is taken out leaving the second piece in the hypo until 5 minutes have elapsed. 5) both pieces of paper are then given a wash in trays; sloshing water and 3 changes for about 10 minutes. These are after all tests and not achival pieces. 6) they are then air dried. The other 2 pieces of paper are treated in exactly the same way but fixed in 15% hypo. Both hypo baths are fresh and dumped after being used for just those two pieces of paper. Is the tonality which appears likely to be fog or stain - and how do you tell one from the other? After all I have read I find it difficult to believe that the paper is not fixed properly. The 3 minute pieces start to show tone first. I use COT 320 with 2% gelatin with 2% Sod. Chloride; 12% silver nitrate with 6% citric acid; straight hypo. Very sorry about the length. Observations/help would be appreciated Colin.