Using gradients to control blur?

[Levada]

You can easily do this if you have PC CS, because it can use a channel to affect the amount of blur. There are ways to do it in earlier versions, but none are as good as the CS (or CS2) solution.

[slipster70]

Oh yeah, I have PS 7. Sorry, should have specified.

[opus13]

what i usually do:

1.make new layer
2.insert gradient of 'foreground color to transparent' where you want the blur to be
3. ctrl-click that layer with the gradient
4. go back to original layer
5. copy+ paste to new layer
6. blur/adjust as needed
7. delete gradient layer (if you want)

[little5points]

You could also switch to Quick Mask mode (Q), create your gradient, switch back to Selection Mode (Q again) and apply the blur filter. It's a quicker, dirtier way to do it

[lokki]

The above technique will work if you only want to apply blur as a translucent plate (say, a window that goes from dirty to clean). But what effect do you really want?

The lens blur in CS allows you to control the strength of the blur, meaning how blurry in terms of how far away from the center pixel in a given area is the edge diffused. This is what looks like depth-of-field.

Alternatively, you can adjust the strength of blur by duplicating a flat layer of your image, bluring it, and applying a layer mask to the blurred layer.

You can also fake the lens blur in 7 by choosing a small blur amount, and reapplying the blur repeatedly over larger and larger areas. This has the effect of edging up on the depth of field, but will take some time.

This may help:
http://www.osborn.bz/dof/

edit** jumped ahead... the post immediately before mine is essentially the same thing as on the link above. The difference is in iterations... use a smaller blur amount with the quick mask, then repeat (CTRL+F) a few times to enhance the effect. Sorry for the confusion!

[VFX Follower]

Okay,

If you have the full version of photoshop (ver.5-CS2) you can do this trick. The easiest way to control a blur with a gradient is this:

1. Copy the layer you want to blur.

2. Blur the copied layer to the most extreme blur that you want to see in the image. I recommend using Gaussian Blur, but any blur will work. Gaussian blur works well to simulate camera blur (for depth of field).

3. Once the blur is applied, create a layer mask to the blurred layer. You should see an icon on the Layers pallete that has a dark sqaure with a white circle in the middle. Make sure the blurred layer is selected and press the layer mask button.

4. Depending on how you have your Layers pallet configured, you should see a white square apear to the right of the layer preview. This box should also have a chain link between them. If you see this, you are on the right track. If you do not see the white square, you problably have thumbnails disabled in your pallet options settings.

5. Select the layer mask. You know it is selected if you see the same icon as the 'create layer mask' button (dark square with white circle) next to the layer preview. In versions 5-CS you have a paint brush icon to show which layer is selected. When the layer mask is selected for a layer, the icon changes to layer mask icon. In CS2, they have removed those icons for the layers pallet and you will only see a highlight box around the layer preview indicating which layer is selected. If the layer you are working with has a layer mask applied to it, you just click the layer mask and you will see the highlight move to the mask.

6. Now that you have the mask selected, you can create a gradient on the layer mask. White pixels indicate opacity and black pixels indicate transparency. Everything in between white and black will be the variation of transparency.

This is a cool technique to fake depth of field in photographs. I hope this gives you a better understanding of how to control your images. Just play around with the gradient tool, you can create some cool images with it, in conjunction with the layer mask tool.

Enjoy!

JB...

[halo]

if you have cs you can just use lens blur. :hmm:

[CGTalk Moderation]

This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.