jaapv Posted February 16, 2013 Share #1 Posted February 16, 2013 Advertisement (gone after registration) I've seen this a few time. Usually when exporting to SFX. I figured it was just banding, but that confused me because I was in 16bit ProPhoto RGB. Silver Efex works in 8 bits. And Profoto RGB has no meaning for a monochrome image as it is a colourspace. Link to post Share on other sites More sharing options...
Advertisement Posted February 16, 2013 Posted February 16, 2013 Hi jaapv, Take a look here Colour space and Monochrom files. I'm sure you'll find what you were looking for!
wattsy Posted February 16, 2013 Share #2 Posted February 16, 2013 Silver Efex works in 8 bits. Works in 16-bit mode when I use it in Photoshop CS6. Link to post Share on other sites More sharing options...
jbl Posted February 16, 2013 Share #3 Posted February 16, 2013 Silver Efex works in 8 bits. And Profoto RGB has no meaning for a monochrome image as it is a colourspace. It comes out of LR as an RGB TIFF so the color space can matter. Link to post Share on other sites More sharing options...
jaapv Posted February 17, 2013 Author Share #4 Posted February 17, 2013 Works in 16-bit mode when I use it in Photoshop CS6. It is greyed out in mine if I am not in 8 bit. I'll have to run through all the settings in that case... Link to post Share on other sites More sharing options...
jbl Posted February 17, 2013 Share #5 Posted February 17, 2013 No it cannot. Grey is grey in all colour spaces. In my case it was post toning, but to be honest, I'm completely confused . Link to post Share on other sites More sharing options...
jaapv Posted February 17, 2013 Author Share #6 Posted February 17, 2013 The colours we use for toning are well within the gamut of even the smallest colour space. The function of a colour space is to describe the colours that can be rendered mathematically. Obviously that has no meaning in black and white photography. I would recommend "Real World Color Management" by Fraser,Murphy and Bunting. It is available at a reasonable price for Kindle. Link to post Share on other sites More sharing options...
mjh Posted February 17, 2013 Share #7 Posted February 17, 2013 Advertisement (gone after registration) As interesting as it is, isn’t all this talk about colour spaces and colour depth beside the point? It isn’t banding/posterisation we are dealing with here. Link to post Share on other sites More sharing options...
jbl Posted February 17, 2013 Share #8 Posted February 17, 2013 As interesting as it is, isn’t all this talk about colour spaces and colour depth beside the point? It isn’t banding/posterisation we are dealing with here. Yep. Didn't intend to take this one off the rails... Link to post Share on other sites More sharing options...
jaapv Posted February 17, 2013 Author Share #9 Posted February 17, 2013 Moved into the appropriate forum Link to post Share on other sites More sharing options...
jaapv Posted February 17, 2013 Author Share #10 Posted February 17, 2013 Works in 16-bit mode when I use it in Photoshop CS6. Very happy my attention was drawn to this. I was converting raw to grayscale 16 bit ( probably paranoid, to avoid unbalancing colour channels) SE only accepts 8 bit grayscale, but 16 bit RGB.... I'll assign an action to a function key. Link to post Share on other sites More sharing options...
Nick_S Posted February 18, 2013 Share #11 Posted February 18, 2013 Silver Efex works in 8 bits. And Profoto RGB has no meaning for a monochrome image as it is a colourspace. Is this really the case for Silver Efex. It sounds like a recipe for posterization and banding artefacts. In which case it would suggest that all major tonal adjustments be done in Lightroom, followed by a final pass though Silver Efex if a particular look is required. ProPhoto colour space has a gamma value of 1.8, not 2.2 used by sRGB, so non-colour managed software such as many web-browsers will not display gray scale images that are in ProPhoto space correctly. Nick Link to post Share on other sites More sharing options...
jaapv Posted February 18, 2013 Author Share #12 Posted February 18, 2013 See my post above yours. Link to post Share on other sites More sharing options...
adan Posted February 18, 2013 Share #13 Posted February 18, 2013 The function of a colour space is to describe the colours that can be rendered mathematically. Obviously that has no meaning in black and white photography. Not entirely. Color spaces are defined (in addition to RGB primary limits) with a "white point" and a "gamma" - both of which may influence grays (essentially, white balance and mid-range contrast curve). Most commonly-used color spaces use a white point of D65, so that becomes moot for the most part. But a middle gray (128/128/128) in a gamma-2.2 color space is a darker gray (visually onscreen) than 128/128/128 in a gamma-1.8 color space. or put another way - the gray that is 128/128/128 in a g2.2-space becomes 110/110/110 converted to a g1.8-space. And if you are printing, the color space of your image gets converted to the color space of your printer via the printing profile, so the grays may change. Link to post Share on other sites More sharing options...
jaapv Posted February 18, 2013 Author Share #14 Posted February 18, 2013 Which is exactly why I use grey Gamma 2.2 16 bit in CS6. In RGB colour values and luminosity are linked, very unpractical for monochrome images. The L channel in LAB is preferable. Link to post Share on other sites More sharing options...
250swb Posted February 20, 2013 Share #15 Posted February 20, 2013 With which types of files does Silver Efex Pro 2 work? Silver Efex Pro 2 works with 8- and 16-bit images; RGB, CMYK and LAB color spaces. Silver Efex Pro 2 will not work with images in the Grayscale mode. When using Silver Efex Pro 2 as an external editor for Lightroom, Silver Efex Pro 2 can support JPEG and TIFF files*. *Silver Efex Pro 2 only supports TIFF files in 8 or 16-bit with no compression or LZW compression. Copied from Nik FAQ Link to post Share on other sites More sharing options...
jaapv Posted February 20, 2013 Author Share #16 Posted February 20, 2013 I convert to lab to use SE and back to grayscale 16 afterwards. No loss that I can see. Link to post Share on other sites More sharing options...
Guest WPalank Posted February 24, 2013 Share #17 Posted February 24, 2013 I convert to lab to use SE and back to grayscale 16 afterwards. No loss that I can see. I keep mine in ProPhoto16 bit all the way through the print with my own machine and with Image Print I sometimes have to uprez an image (have the RIP create pixels) when it is severely cropped and I am printing large and I see no banding or artifacts....... This moving in and out of spaces is pure gibberish with MM images. Link to post Share on other sites More sharing options...
jaapv Posted February 24, 2013 Author Share #18 Posted February 24, 2013 It's no hassle - But whatever works works. Link to post Share on other sites More sharing options...
wattsy Posted February 24, 2013 Share #19 Posted February 24, 2013 It's no hassle Probably not but I'm with William on this. Switching in and out of colour spaces in this context – "( probably paranoid, to avoid unbalancing colour channels)" – seems a bit like voodoo. Link to post Share on other sites More sharing options...
erudolph Posted February 24, 2013 Share #20 Posted February 24, 2013 I keep mine in ProPhoto16 bit all the way through the print with my own machine and with Image Print I sometimes have to uprez an image (have the RIP create pixels) when it is severely cropped and I am printing large and I see no banding or artifacts.......This moving in and out of spaces is pure gibberish with MM images. Hi William, I have a couple questions about your use of Imageprint. You keep your files im the ProPhoto space all the way. For monochrom images do you use a color or gray scale IP profile? And with your workflow, are you getting good softproofing from within IP? From the IP user manual and from talking to their tech support I'd developed a different workflow, but am curious about yours. Link to post Share on other sites More sharing options...
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