Many thanks for the feedback and the 'just selenium' test is certainly worth while. I will have another run of tests when I can get hold of some more papers.
There has to be a certain amount of compromise in making comparative tests, no matter how accurately they are made. I feel I have let down the Bergger paper because the developer didn't suit it and so the results makes a superb paper look a bit washed out.
'rternbach': Have a look at the chart page which lists the properties of all the papers tested and if they are variable contrast. Yes I love variable contrast paper but to make a full reply would take up more space than this page would allow! We all regret the demise of some of the old classic fixed grade papers but we have to move on and use what is now available.