Need help with: Photoshop Blur Technique
gregwalker (5 pencils) | Thu, 2005-03-17 18:01This is a Photoshop technique that is used on images but Im sure it could be applied to many different areas of graphic design.
If you go to: http://mute.rigent.com/index.php?ladat=2005-03-08 you will see an image of a street car. This artist has used Photoshop layers to apply a blur to masks, here is how he explains it;
Quote taken from: http://mute.rigent.com/index.php?ladat=2005-03-08#comments
Quote:
What I do with photoshop is separate the different visual planes in the image using a layer mask, light for in focus to dark for out of focus. The lens blur filter in photoshop CS then uses the layer mask as a guide to blurring the image. There's a bit of trial and error finding the right layer mask 'silhouette' but eventually you should be able to get a result you're pleased with. Once you've applied the blur turn the layer mask off to see the effect. It really is that simple, the only hard part is creating the layer mask. For this shot I filled in the streetcar with white, then used various shades of grey for other objects as they visually receded, like the cars on the left, until I left the buildings in the background as black. If you create a gaussian blurred layer underneath the one you're working on you will have a 'preview' of the final image, but I find gaussian blurring to be too soft for the final image.
My question: He talks about filling different layers with white and shades of grey, is he painting over the areas on the layer mask, then applying the blur? I am very unclear about how to apply this technique to images. Can someone explain this method in much simpler terms?
Here is other example of this technique:
http://groundglass.ca/archives/2005/02/28/van.php
Any reference materials/ tutorials on using layers and blurs would be appreciated.
~greg
Commenting on this Forum topic is closed.
You can use an Alpha Channel, as well. In the photo, select items in the photo (with lasso, quick mask, etc.) and then switch to the Alpha Channel and fill that selection with white (focus), gray (some focus), or black (out of focus). This creates a depth map for the lens blur to use. For more realistic effects, you can use gradients and smoother selections.
In the Lens Blur dialog, select your Alpha Channel as the depth map, turn off "Invert," and start tweaking the other settings as needed.
Simply put: the filter uses your Alpha Channel and apply an amount of blur based on the shade of gray used. White gets no blur, grey is blurred some, and black is blurred a lot.
A quick visual tutorial of this is at:
http://www.computer-darkroom.com/tutorials/tutorial_9.htm
this is the poor man's depth of field. more and more photographers are trying to capture everything in the image sharp and than fake the depth of field in PS. i think it's very superficial, but nothing wrong with that. i like the effect, however in my opinion the examples you posted are not done very well. i mean technically they are good. but their effect is very unreal.
basically the lens blur is a new feature in PS CS at as bteverybody said it uses a gradient between white and black to define depth of field. whites are sharp and blacks are out of focus. everything in between is an effect in between the two extremes. the better you create this grayscale layer, the better your fake depth of field will be. the hard part is to separate objects in your image. as the blogger said, it's a bit of a trial end error method.
here is a great tutorial movie (20MB!)
from Russell Brown
http://www.russellbrown.com/images/tips_movies/Hocus%20Pocus%20Focus.mov
Fine Art Framed New Orleans Photography
http://www.nolaPIC.com
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