Colour management - is my lightbox letting the side down?

[dave_whatever]

Since I've recently got hold of a scanner I've taken the opportunity to get me monitor properly calibrated and profiled (instead of doing it by eye) and last week got hold of a Faust Velvia target for scanning. So now I've got input, computer and display all singing from the same hymnsheet - great, couldn't be happier. However it now seems to be the my lightbox is the weak link in the chain.

Basically my film on the lightbox still doesn't look exactly the same as a scan (with the scanner profile applied) in photoshop in terms of colour. I did a couple of quick scans this weekend and both of them look a lot more magenta/warmer on the lightbox than they do on screen. Incidentally if I hold the film against the monitor on a white background it does look about the same colour-wise as the scan, albeit obviously a lot darker, which makes me think that at least the scanner and monitor profiles are doing their jobs.

This got me thinking of a couple of scenarios:

1. My monitor is set up for gamma 2.2 and whitepoint at 6500k as I kept reading this was the de-facto standard for RGB work. However my lightbox is churning out light at 5500k. So does this mean that they're always going to look different in terms of colour temp?

2. My lightbox (a ~£60 flat job) would well be prompting some metamerism from the film and making certain colours look stronger than they would be with an ideal lightsource, in this case warm/magenta in velvia.

So just wondering if everyone else experiences something similar, or you just trust the monitor/scanner and ignore the lightbox? Or get a 6500k lightbox, or set monitor to 5500k? Am I being to anal about the whole colour management thing?

Thanks.

[craigmagee]

Dave your being far to anal about it all
How do you want the final result to look? as it does on the lightbox? held up against the monitor? held up against the window?
Thats the most important thing!! If you want it to look as it does on the table, just tweak it in the scanner software.

Worry more about the difference between monitor and printer!

As for the color balance of the velvia, i've always found it to have a warm/magenta cast to it anyway!

[Joanna Carter]

So, if you open a blank window in your favourite web browser/word processor, then use the screen as a lightbox???...

[dave_whatever]

So, if you open a blank window in your favourite web browser/word processor, then use the screen as a lightbox???...

Incidentally if I hold the film against the monitor on a white background it does look about the same colour-wise as the scan, albeit obviously a lot darker,

[scovell001]

Dave,

I completely agree with Craig Magee. Worry more about the prints against the monitor.

L* has a far more neutral grey rendering intent than Gamma 2.2, if your monitor calibration software offers it, I'd recommend it over G2.2.

D65 is the 'web viewing standard' for white balance, and I'll admit now, I've calibrated my Eizo CG241W monitor to D65 (6500K) simply because I've grown up with it, and don't like the slightly warmer calibration of 5800K (recommended by Neil Barstow) which more closely matches the white of most inkjet papers and to a certain extent transparency viewers.

There's also the monitor brightness (but as you haven't mentioned it, I won't talk about it).

Transparency viewers are like homemade cakes 'every one tastes different'. They're on the most part too bright (I have a black card mask on mine in the shape of the tran I'm viewing, its still too bright but it helps). The important bit for you, is the bulb inside the viewer might be classed as D50, but the frosting in the defuser will change this and also yellow over time.

You could measure the light from the lightbox and calibrate your monitor to this value, If you do, it'll give you problems when matching prints against the screen.

As already mentioned in this post, the lightbox is for reference purposes only, and yes, no one here really worries about it. It should be placed at 90 degrees or more from your screen viewing position & be completely out of the field of view when your looking at the monitor. The idea is, you look at the tran on the lightbox, then turn and view the image on the screen. If you view both at the same time, the white balance/brightness will throw you off. The only current solution is the GTI adjustable transparency viewers (big bucks).

Enjoy, & more reference material can be found here under soft-proofing tips: http://www.hutchcolor.com/CMS_notes.html. I'm sure others will chip in with their views too.

[dave_whatever]

Cheers for the input there Ian, much appreciated.

Interesting point about the difusers yellowing over time - i have got a spare lightbox which is pretty old and is VERY warm.