I made a Maxim plugin that implements the Photoshop blending modes once upon a time. The equation used for each mode is displayed on the plugin dialog, see here for description of each:
http://www.simpelfilter.de/en/basics/mixmods.html
You can get the plugin here:
http://www.faintgalaxy.com/code.htm
I haven't tried it with recent v5 release so YMMV.
My processing log for M82 contains (see below for the whole mess!):
a comment about using Pin light PSBlend of the HAlpha data with the red channel (after doing a Split Triclor on the LRGB), then redoing a color combine of the B+G channels + blended R channel.
Although now in Maxim v5 you can recombine color channels obtained from Split Tricolor using the Color Stack dialog.
The very old result can be seen here:
http://www.faintgalaxy.com/ngc3034.htm
HTH
NGC3034_ProcessingLog.txt
BDF calibration with bad pixel map, F bias subtracted only
Align all (RGB and C) to best FWHM C frame 066C
Combine Sigma clip: 3 sigma, ignore black and pix>55K
RGB are 600s x 8 frames: 80 min per
C is 120s x 74 frames: 146 min
Ha is 530 min however the dome obscured the scope a fair amount (30% ?)
01X series
C FWHM=2.5"
CRGB Flatten bgd manual mode
C Double sized for LR
C LR 3 iterations with ~6 PSFs
C Half Sized
C FWHM=2.2"
CRGB Crop 50,20 x 1375,980
LR06-01X
C Double sized for LR
C LR 6 iterations with ~7 PSFs
C Half Sized
C FWHM=2.0"
Crop 50,20 x 1375,980
However the nebulosity at all intensity levels look the same.
Remove pedestal
B = 336.5
G = 574.0
R = 512.5
C = 565
LRGB combine
Lab, AutoBgd=on, Lw =100%, 1:1.03:1.25
DDP: Bgd=90, Mid=700, Filter=KPLM
Remove Bloom: 3 stars
Levels: RGB: gamma ~0.5, blue white point down ~10%
Remove bgd color: Threshold=5500, Feather = 10
Edit Pixels (-ep1 and -ep2): fixed left over from Remove bloom 2 brightest stars
Clone: Red enhanced version (115,110,105,102%) in halo around brightest star
Clone: GaussianBlur 1.5% (3 brightest star), 1.2% and 1% versions
01XHa
Aligned to -01XC
Combine Sigma clip: 3 sigma, ignore black and pix >55K, 19 frames used
Threw out frames:001-004,009, kept 4 x 20min + 15 x 30 min = 530min = 8.8hrs
Flatten Bgd manual mode
Crop 50,20 x 1375,980
Remove pedestal: Ha = 203
PSBlend: Pin light with R frame fbgd-crop-beq-rb-01XR
Split Tricolor: LR03-rb-LRGB-01X
Color combine RGB with 1:1:1 using PinLight frame for R
DDP: Bgd=90, Mid=400, Filter=none
UnsharpMask: KLPM, 75%