Soft Proofing is the process of trying to colour match what we see on screen, i.e. when we are designing, with the actual printed output. Your image will have a larger colour space than will the printers it is sent to, so there needs to be a way of understanding and controlling that difference.
So, you already have the image you want to proof set to use the Adobe RGB (1998) colour profile, and now we need to check that against the colour profile for the fabric printer.
For this to work completely, you will need to have calibrated your computer monitor, for which you use a colorimeter. We use the "X-Rite ColorMunki Display Calibrator for Monitors, Projectors and Tablets" colorimeter. It is easy to use, and it allows you to understand from looking at your monitor pretty much what your prints will look like. It's a little expensive for the hobby user, but perhaps an essential tool for the student or professional. Perhaps you could borrow one for an evening?
If your monitor is not calibrated, this process will still be useful, but just a little less useful.
To use the ICC file, save it to the following directory for use with your design program: \WINDOWS\SYSTEM32\SPOOL\DRIVERS\COLOR
For Windows 8, download the file to your download directory, then right-click the filename, then select "install ICC profile".
ICC profiles can be saved in two locations within MacOS:
In Photoshop, Select View, Proof Setup to select the printer colour profile against which you want to check your image; i.e., the correct Lacuna Press printer ICC Profile.
This setting pushes all colours that are outside of the colour space selected into that colour space. This is the setting that we use when we print.
This setting adjusts all the colours in the image so they all fit within the colour space in a manner that relates them to each other perhaps more naturally. We do not use this setting.
We use this method of managing relative shades of black. This ensures that the monitor's black is equal to the printer's black. Make sure this is selected when you are soft proofing for a Launca Press print.
This setting converts the image's on-screen white to match the color temperature of the fabric to be printed on.
This compresses the dynamic range of your on-screen image so that it more closely matches that of the print. It works by lightening the image's black until the dynamic range has been sufficiently reduced (with all other tones being shifted accordingly).
This ensures that the monitor's black is equal to the printer's black.
Soft proofing gives a much more accurate impression of what this image will look like printed on Lacuna Press fabric. Of course, you may now want to go and adjust that image to get it closer to the actual printed outcome you have in mind.
Once you have set up your custom settings for soft proofing, you can proof colours by toggling on/off with [ctrl]+[y], or by selecting View, Soft Proof Colors.