[robski]

Thanks for the Tip Clive

I don't normally print by ink Jet, laser jet or Photo Lab so I have little experience of real world problems.

Earlier this year I used an on-line lab in Guernsey mainly because their 8" x 10" were a fraction of the high street prices.
Not having much experience of setting up images of photo lab work I sent a small batch off. One of the shots was for a neighbour which was mainly monochrome. On return the colour shots were passable could do with a bit more punch. On the mono shot I could detect a slight green tinge in the mid tones. When viewed in daylight it was more noticeable.

Anyway the neighbour was happy enough with the results, but it was niggling me.

I sent a second batch of colour with a bit more contrast and brightness plus a gray scale wedge.

At work I have a spectrocam where I can take spot readings of the gray scale wedge.

Attached are 2 graphs of the readings at Daylight (D65) viewing and normally commercial viewing (D50).
A few things to note the daylight (D65) spectrocam reading does appear a tad greener as the real life viewing in daylight indicated. The printed solid black is about a 5% black in RGB terms. Shadow detail starts to appear in the region of 15% to 20% in terms of RGB. The readings at 255 are in fact reading the Fuji crystal archive photo paper which is a hard blue white. Lower down the scale the blue channel is some way behind the the red and green. I have noticed that images out of my camera have a bias towards blue, maybe to offset the lack of blue in photo lab work.

I tweaked the neighbour's shot to pull up the shadow and add a touch of blue and sent a 3rd batch.
The results were better but not what I would regard as perfect. I let the neighbour have the updated version FOC and she did agree it looked better. Not that she was unhappy with the first attempt.