Friday, November 26, 2004
Masking for color correction in preparation for giclee printing
Our giclee printing studio processes a sizeable amount of files daily. Pretty much everyone of them needs localized color correction. I will quickly explain some of the tools and techniques we use in Photoshop to accomplish area masking. Be advised though that some parts of this dissertation requires either intermediate or advanced knowledge of Photoshop.
First, the tools. As for hardware, we use a Wacom tablet. The reason is that when a mask needs to be brushed, we can control pressure and therefore create an organic shape, with no hard edges. For example, if we were to try to isolate an object that has been photographed with selective focus, where the front edges are sharp and the back is soft, the only way to do this is to brush a mask with very little feather in front and more feather in the back. Yes, you can do it with a mouse but it would take 3 times as long and it would not be as clean!
Second, the soft tools in Photoshop: the magic wand is a good starting step when homogenous areas are present, such as a white background. Tolerance can be adjusted to be able to grab what is wanted. Color range is even better because you can preview your results. To make the perfect mask, the best way is to quickmask. Press Q on the keyboard and make sure black is selected as your foreground color. When you paint the mask, you can preview the ares that are being masked out (not selected). When done, press Q again and the mask will turn active. You can save the mask as an alpha channel. Remember, what you are masking is the area that will not be affected by the selection (There is a way to change this but we assume Photoshop defaults). You can still paint an area you want to select, such as a small object: make the selection active, and go to the top menu -> select->inverse and the area you masked will turn into your active area. There are many other ways to mask and many other tools. If you have a request, please e-mail us or post a comment and we will be happy to comply!
First, the tools. As for hardware, we use a Wacom tablet. The reason is that when a mask needs to be brushed, we can control pressure and therefore create an organic shape, with no hard edges. For example, if we were to try to isolate an object that has been photographed with selective focus, where the front edges are sharp and the back is soft, the only way to do this is to brush a mask with very little feather in front and more feather in the back. Yes, you can do it with a mouse but it would take 3 times as long and it would not be as clean!
Second, the soft tools in Photoshop: the magic wand is a good starting step when homogenous areas are present, such as a white background. Tolerance can be adjusted to be able to grab what is wanted. Color range is even better because you can preview your results. To make the perfect mask, the best way is to quickmask. Press Q on the keyboard and make sure black is selected as your foreground color. When you paint the mask, you can preview the ares that are being masked out (not selected). When done, press Q again and the mask will turn active. You can save the mask as an alpha channel. Remember, what you are masking is the area that will not be affected by the selection (There is a way to change this but we assume Photoshop defaults). You can still paint an area you want to select, such as a small object: make the selection active, and go to the top menu -> select->inverse and the area you masked will turn into your active area. There are many other ways to mask and many other tools. If you have a request, please e-mail us or post a comment and we will be happy to comply!
