Colour profiles

[kaiser]

Hi everyone,

Did a quick search but I am still a bit confused...

Am PP pics to put on a DVD slideshow. The RAW (NEF) files are tagged as Adobe RGB and that is what I am working with in Capture NX2. When converting to jpeg should I changed the colour profile to sRGB if its going to be viewed on other people's LCD monitors or HDTVs?

Also, in NX2, when given the option to change colour profile of a RAW image, there are several options given when you choose to convert profile, under a sub menu titled "Intent"

these are: 1. Perceptual, 2. Saturation, 3. Colourmetric, 4. Absolute Colourmetric.

Is there a particular option that I should be using? The default is perceptual.

Thanks,

matt.

[jev]

Definitely convert into sRGB before exporting them yes. Rendering intent "perceptual" will result in a little softer looking images that are compressed in color if the source profile is bigger than sRGB, colorimetric just clips anything that doesn't fit the sRGB space. See here for the full story. It depends on what you want to emphasise, but usually perceptive is best when converting to TV's (they usually are too saturated anyway).

[kaiser]

Thanks for that jev.
So when converting the colour profile of a RAW file from Adobe RGB to sRGB during the jpeg conversion - I should be okay as long as I don't save that colour change to the RAW file. Ie. if I want to keep working with that RAW file in AdobeRGB later on?
Cheers.

[jev]

Yes, you should be okay with that workflow.

Whether or not you could safely change the colorspace in NX2 depends on the converter. Since I don't use NX2 I cannot tell how it would affect the photo there but I think it's safe to assume that NX2 does not alter the actual RAW image but instead just adds information in a sidecar. In that case, you could safely work in sRGB in the NX2 software whilst still keeping the full color space. You could always try what happens using a copy of a RAW file ofcourse.

[kaiser]

Thanks mate. In NX2 you can either "apply colour space" to an image or "convert to" colour space. The former option shows an immediate change to the image whilst the latter has no visual effect.
I have NX2 defaulted with Adobe RGB workspace, I am able to convert to sRGB > save as jpeg - then revert to the original RAW file in AdobeRGB with no noticable losses.

I'm still encountering issues when I upload images and view them here in Mozilla Firefox - they appear washed out with greyer blacks (if that makes sense) and a little desaturated. They were definately converted to sRGB and confirmed this when looking at the image properties. They look fine when I view them in NX2 or Preview on my desktop. I'm working off a glossy MacBook screen which doesn't help things at all. Makes me want a decent monitor even more.
Thanks for the advice.

[jev]

In NX2 you can either "apply colour space" to an image or "convert to" colour space. The former option shows an immediate change to the image whilst the latter has no visual effect.

Always convert, never assign. You want the colors to look the same (where possible) and that means the pixel values must be recalculated. Compare it to the speedometer in a car: in the civilized world, the speed shown on the speedometer is in km/h. In the USA, they still show miles/hr (mph). If you want to convert the speed information from km/h into mph, you need to divide the numbers by 1.6 (for convenience, in reality it's a bit more I think). That is what happens if you convert color spaces. If you just assign a colorspace, you'ld take the reading from the km/h speedometer and interprete that as mph - you'ld go a whole lot faster. In colorspace terms: assigning would keep the numbers but the colors look differently.

I'm still encountering issues when I upload images and view them here in Mozilla Firefox - they appear washed out with greyer blacks (if that makes sense) and a little desaturated.

That is weird. If you post an example (same image, once without conversion [thus, in AdobeRGB] and one with conversion [in sRGB]) we can have a look.

[arthurking83]

....Since I don't use NX2 I cannot tell how it would affect the photo there but I think it's safe to assume that NX2 does not alter the actual RAW image but instead just adds information in a sidecar. In that case, you could safely work in sRGB in the NX2 software whilst still keeping the full color space. You could always try what happens using a copy of a RAW file ofcourse.

that's how NX works. Regardless of what colour space you use for the RAW, it's convertible to any/either without any loss of colour.

It's only when you create TIFF's and JPG's, that the colour space then may become an issue, mainly when you want high quality prints form pro labs or some such service.

** Annoyances! **
In View NX you can set an option to convert jpgs to sRGB only, whilst maintaining adobeRGB for the NEF if you wish, but you don't get that flexibility in CaptureNX, which is supposed to be the fully featured image editor!?
Problem is that you can't use ViewNX to convert NEF's that have been edited with CaptureNX!

One day Nikon will fully realise all of the little incompetencies of their software, and find a company that knows how to create software properly!
It's not really an issue as such, just annoying in some ways, and most certainly avoidable as the two softwares share code!


** NOTE!! **
In CaptureNX when you're changing preferences in that colour management applet, make sure if you want to change the colour space that you tick the small box under the option to do so, where it says use this instead of embedded profile
. If that's not box is not ticked, and you set it to convert your adobesRGB's to sRGB, they remain as adobeRGB even though you think they are being converted!
(guess who that happened too! )

[kaiser]

** NOTE!! **
In CaptureNX when you're changing preferences in that colour management applet, make sure if you want to change the colour space that you tick the small box under the option to do so, where it says use this instead of embedded profile
. If that's not box is not ticked, and you set it to convert your adobesRGB's to sRGB, they remain as adobeRGB even though you think they are being converted!
(guess who that happened too! )

Box is ticked, thanks