B & W photo conversion in photoshop

found this on the forums, so i'm posting it here for my reference

here's a list of the values for the red, green and blue for the channel mixer when you want to convert a photo to black and white.
paper Red Green Blue

Agfa 200X 18 41 41
Agfapan 25 25 39 36
Agfapan 100 21 40 39
Agfapan 400 20 41 39
Ilford Delta 100 21 42 37
Ilford Delta 400 22 42 36
Ilford Delta 400 Pro 31 36 33
Ilford FP4 28 41 31
Ilford HP5 23 37 40
Ilford Pan F 33 36 31
Ilford SFX 36 31 33
Ilford XP2 Super 21 42 37
Kodak Tmax 100 24 37 39
Kodak Tri X 25 35 40


you can change the values to what you want but the sum of the three values must be 100