Pro photo blues

[pco98]

Hello all,

I'm scanning slides in with Vuescan and a prophoto colour space.

Most of the images look great but ones with really blue skies which I've polarised to the max look saturated to the extreme. I am also seeing very noticable uneven gradutation into the deeper blues. A very noticable pixelated border - not smooth tonal change. Is this what is referred to as banding?

Any tips to avoid this? Or do I have to rescan in Adobe RGB

Kind regards,

Ross

[digitaldog]

Hello all,

I'm scanning slides in with Vuescan and a prophoto colour space.

Most of the images look great but ones with really blue skies which I've polarised to the max look saturated to the extreme. I am also seeing very noticable uneven gradutation into the deeper blues. A very noticable pixelated border - not smooth tonal change. Is this what is referred to as banding?

Any tips to avoid this? Or do I have to rescan in Adobe RGB

Kind regards,

Ross
[a href=\"index.php?act=findpost&pid=179268\"][{POST_SNAPBACK}][/a]

Doesn't sound like a color space issue. I doubt you'd see any visual difference with Adobe RGB (1998).

[NikoJorj]

Most of the images look great but ones with really blue skies which I've polarised to the max look saturated to the extreme. I am also seeing very noticable uneven gradutation into the deeper blues. [a href=\"index.php?act=findpost&pid=179268\"][{POST_SNAPBACK}][/a]

What bit depth are you using?
Couldn'it also be a profile-related problem?

Just thinking out loud...

[Jonathan Wienke]

If you're experiencing hypersaturation, your scanner software is probably outputting sRGB or Adobe RGB regardless of whether or how the output is tagged. Assigning ProPhoto to such files will result in oversaturation

[Mark D Segal]

Not sure I agree with Andrew on that point - I've had experience scanning film where excessive saturation was resolved by scanning to a narrower colour space than ProPhoto. The best way to know is to experiment. Change the colour space to ARGB(98) and see whether that helps. If your scanner is capable of 16 bit/channel I would also recommend using this feature, as that would mitigate banding/posterization.

[David Good]

If it's not the polariser/lens combo (wide angle?), then it could be the scanner or the  profile if you have one for that transparency type. You don't mention what scanner you are using.
VueScan is very capable software when properly configured, such as setting the Media type to Image. I prefer to assign /convert in Photoshop. (not that again!)

[pco98]

Hello again,

A little more detail - using Konica Minolta Dimage Scan Elite II 5400 dpi which is a 16 bit scanner (although a test review at photo-i.co.uk is perhaps worth mentioning. His impression:

Using 16 bit hasn't made a great deal of difference to the overall quality of the image, nor has using the Multi sample scanning feature reduced the noise. To me this indicates that this may be an 8 bit scanner that is using software algorithms to simulate 16 bit scanning, but not with much success.)
http://www.photo-i.co.uk/Reviews/interacti...mage/page-7.htm

Not sure if this is a hardware issue or just the lame bundled software - any thoughts? Anyway I scan with Vuescan on 16bit multi pass mode. It has the ability to do a second pass exposure to bring out more detail in the shadows but I turned this off for these polarized scans as this makes it even more saturated.

Looking at them again it may just be a noise issue which is more noticable in the wider colour gammut. It seems like the noise makes the colour graduation not smooth creating a noisy border between the darkest shade of blue and the rest. This highlights the lack of a smooth transition. I don't have a lot of familiarity with noise's weirder effects.

Will try scanning in Adobe RGB and Vuescan's RAW format (adding profile in camera raw) tonight.

Thanks for your thoughts,

Ross

[Mark D Segal]

I use the original Minolta Scan Elite 5400. It is a 16-bit scanner. It does not make noisy scans. Anyhow your problem does not sound to me like the result of noise. It sounds to me like too little data trying to fill too much (colour) space.