From our “What should we write about next? came an idea from Lynn Noah. Lynn wrote: “Now that CS6 and LR4 are out, and many more photographers seem to be using and printing from LR4, it would be very helpful to review the Piezography workflow. LR4 printing is extremely convenient, but when I import my files in grayscale 2.2 from C1 or a scan LR changes them to ProPhoto which is 1.8. I try to soft proof to QTR RGB Photo Paper or Wide Gamut RGB and then in the print module choose one of those two, but there is nowhere in LR to read what profile is assigned to my file for sure and the process becomes confusing. LR offers many advantages in the Develop module, but when I go into Photoshop for additional edits and then save to LR, I am uncertain what my profile is. Your views on the CS6/LR4 workflow for Piezography would be much appreciated.”
It does seem incredibly confusing, but it’s not really.
When you import your photos into Lightroom, they are not actually converted from Gamma 2.2 to the Gamma 1.80 of Lightrooms ProPhoto RGB space. Lightroom 4 does not always use ProPhoto RGB as it’s internal color space as is widely believed. In the Library module for example, it uses Adobe RGB color space to preview everything. The Develop module also displays in the Adobe RGB color space. The only way to escape working in Adobe RGB is to actually select a Soft Proof profile. So Lightroom is using a gamma of 2.2 to display all your images to you, unless you select a Soft Proof profile that differs from Gamma 2.2 or from Adobe RGB.
When does Lightroom then actually use ProPhoto RGB? When you transfer an image to Photoshop via the Photo / Edit In menu item. But, you can override that by changing one of the Lightroom Preferences.
When you select to edit the image in Photoshop, Lightroom will use the internal color space of ProPhoto RGB unless you have set the “External Editing” Preferences to the color space of Adobe RGB. If you select this preference – then images from Lightroom which are transferred to Photoshop will be in Adobe RGB which has a gamma of 2.2.
If you are using Lightroom to export tiff format images which you print in Windows version of QTR – no conversion takes place from the Adobe RGB if you select Adobe RGB in the export preferences.
When you print from Lightroom directly to QuadTone RIP on Mac OS, and you select in the Color Management Pane, “Profile: Managed by Printer” – then Gamma 2.2 is transferred directly to QuadTone RIP.
So it is actually very straightforward to use QuadTone RIP from Lightroom.
Just remember that profiles for QuadTone RIP are only chosen in QuadTone RIP. If you are using Piezography inks, you should only SoftProof to Piezography softproof ICC profiles which you can make using QTR Create ICC and and Eye One spectro. Otherwise, if your display is calibrated to Gamma 2.2 and your brightness is not over 85l or candelas – they you are very nearly calibrated for Piezography.