Saturday, October 31, 2015

From Photo to Thermofax Screen

Have you ever wanted to turn your own photo images into thermofax screens?  We are happy to make custom screens from your images.  A lot of the screens in our Etsy shop are from photos we have taken.  We use Photoshop Elements to convert our photos to screen images.  While not all photos may fit the exact same process, there are some basic steps for  converting a photo to a screen image.  If you can take the object out of its natural environment and photograph it against a white or black background, or take photos with a single color background such as water or sky, it makes the task a bit easier.

The first step is always to save your original photo under a different name so the original remains unchanged.  That way you always have a copy to go back to if you need to start over.  Here's a photo of a ginkgo leaf against a black felt background.  Once you've saved it to a new file name, you want
to crop your photo to get rid of the excess background.  Come in as close as you can to the object - that way your dimensions will be the object itself, not the object plus background.
Below is a portion of the toolbar that shows the tools we'll use for this image.  Be sure the foreground color is set to black - this will make a difference when you apply a filter.
After cropping, the next thing to do is change your image to black & white.  Thermofax screen images need to be black & white (no gray) in order to burn a satisfactory image.  Go to the Enhance menu and choose Convert to Black and White.  The dialog box below will open up.  You have several styles to choose from and can also adjust intensity.  Try them all - what works best for one image may be totally different for another.  In this case, I chose "infrared", but quite often I use "newspaper".  What you are trying to do is create a high contrast black & white image that shows details.  In this case, infrared seemed to show more texture in the leaf.  When satisfied, click OK.  (We should note however, that sometimes we remove background before changing to black & white.  It just so happens that with this particular image, it's easier to obtain an outline in the image by changing to B & W first.)
Your image file now looks like this.  It's good to save your file at this point, again with a new name, so that if succeeding steps don't turn out exactly as you want, you have this step to go back to rather than starting over.
There are several paths you could take next, and a lot is trial and error to find the process that works best for any given photo.  One option is to get rid of the background first, and then apply a filter to get the effect you want.  Another choice is to apply a filter and then remove the background.  Typically we remove the background first, but found that with this image, applying the filter first gives the image a stronger outline.  To apply a filter, go to the filter menu; there are lots of choices!  The filters we have found we use most frequently are in Sketch, either photocopy or stamp.
This is what it looks like with the filter applied.  (Note - as mentioned previously, the foreground color needs to be set to black to keep the filtered image black & white.)
Next we'll get rid of the background.  Again, there are several ways you might do this, and it also depends on what version of Photoshop Elements you have.  The eraser tool has both a background eraser and a magic eraser.  However, because the background is mottled instead of solid, the basic eraser works best.  (Again, try the various options to see what works best.)  There is another option if you have Photoshop Elements version 11 or earlier - that is a tool called the Magic Extractor which is found in the Image menu.  (If you have a later version, we'll cover that next.)  When you choose the extractor, the window below opens.
You use the red marker to identify the areas you want to keep, and the blue to mark areas to remove.  Choose the preview tool (circled) to see the results before clicking OK; that way you can still edit. The preview looks like this.
You can see that the image, including the outline, remains intact, with just a bit of clean up needed around the edges.  That can be done with an eraser after closing the extractor.  If you're satisfied with the preview, click OK.  If not satisfied, you can do some additional editing.
Before (above) and after (below) cleaning up the edges with the eraser.

What if you have a newer version of Photoshop Elements?  After version 11, there is no more Magic Extractor.  Well, here's an alternative method.  After applying the filter, you can remove the background with the eraser tool.
Start with the Magic Eraser and click in the background spaces around the leaf.  It should take away most of the mottled background; just be careful - if you see dramatic changes to your leaf such as the outline disappearing, go to Edit > Undo (or Ctrl Z).  Remove the remainder of the background with the "regular" eraser; you may have to zoom in on the image to erase close to the outline of the image and use the size slider to change the size of the eraser.

Another alternative to the magic extractor in version 12 and newer is the quick selection tool, although that is more challenging for this image than the eraser.
If using the quick selection tool, click & drag over area you want to select.  Use the add/subtract tool at the bottom of screen to add/remove additional areas.  Then click Refine Edge; adjust the edges as desired.  Click “Output To”; select New Document.  Go to File, Save As to save & name this new version of your image.

After you have removed the background, save your file again, adding height and width to the file name - this is your original size.  This way your file can be adjusted to various sizes depending on the project you have in mind.  To resize an image, go to the Image menu and select Resize > Image Size.
Type in one of the dimensions you want; the other will adjust automatically as long as you have constrain proportions checked.
Again, save your image as a .jpg (image) file with the dimensions as part of the name.  You will end up with multiple files through this process, both photoshop files and image files, so being specific in your naming convention helps avoid confusion.  I would name this ginkgo4x3.7.jpg.  It's also smart to organize all the files for one image in a folder. Finally, your image is ready to be made into a screen and then the fun begins when you can start printing!  Here is this particular image printed on fabric.
Although this tutorial may seem very long, the process itself goes faster, so don't let the length deter you.  As mentioned earlier, there is not one specific process that works for every image.  But once you've had some practice with a variety of photos, it is easier to know what will work best without as much trial and error.  In future posts, we'll add some tips for other types of images.  Give it a try and see what you come up with!

Copyright pgfiber2art 2015. You are welcome to print out this tutorial for your own personal use but please do not share printed copies. We ask that you refer others to this page who may interested in learning about this process.  Thanks!

1 comment:

  1. Thanks for your lovely tutorial and explanation that were taken so well. We really appreciate it.