For some odd reason Adobe removed the slider for the Transparency panel some time ago, and replaced it with a mostly useless drop-down menu of 10% increments. While many users certainly aren’t happy about this, they probably don’t know that you can adjust transparency more precisely than the drop-down menu allows using keyboard shortcuts.
With the object(s) you want to adjust selected, click in the Transparency panel’s amount input box and use the following keyboard shortcuts:
- Increase/Decrease Transparency by 1% = Up or Down Arrow Keys
- Increase/Decrease Transparency by 2% = Option + Up or Down Arrow Key
- Increase/Decrease Transparency by 10% = Shift + Up or Down Arrow Key
While most people know you can adjust the transparency of layers and brushes in Adobe Photoshop manually by using the sliders in the appropriate tool panels, many don’t know you can do it easily with just the keyboard. To adjust the transparency of a layer using the keyboard, simply click the layer you wish to adjust and type the percentage of transparency you wish to use. If you want the layer to be 54% transparent, just type 54. The same tip works for adjusting the flow (transparency) of brushes. Just select the brush tool (hit the “b” key) and type a number. If you want the brush to have a flow of 35%, just type 35. I love this tip for making small adjustments, rather than using the picky sliders which always seem to be a pain to make accurate adjustments easily.
Long, long ago, Adobe gave us transparency in InDesign version 2. In each subsequent version of InDesign, Adobe has added ways to enhance documents with transparency, making it even more enticing. There’s one thing that hasn’t changed, however, and that’s the need to flatten transparency for output to a PostScript device. In the article 
If you place a PSD file with a transparent background into Adobe InDesign and export it as a high-res PDF, you may notice that the edges of your placed image look horrible. There’s usually a black & white halo around the edges of the transparent PSD (see the image above for example). You won’t see them on a placed TIF file, and they generally don’t print anyway, but they’re annoying nonetheless. Fortunately, Bob Levine at InDesignSecrets has finally spilled the beans on what the problem is, and how to fix it. In most all cases, it’s as simple as turning off the Smooth Images feature in Acrobat. Read 
With InDesign CS3 came yet another useful tool that prevents the need to switch to Photoshop to alter an image you’re using in your page layout. It’s called Gradient Feather, and you can find it under the normal Gradient tool in the InDesign Tools panel. Of course adding transparency to your image directly in Adobe InDesign is nothing new. If you recall, InDesign CS2 offered a simple feather feature to your images, but in a limiting manner in which the feather applied to all sides of the image at once. Not very useful in my opinion. 
With CS3, we can now select the image in our layout with the direct selection tool, then select the Gradient Feather tool by either clicking and holding the Gradient tool in the Tools panel and selecting the Gradient Feather from the flyout menu, or simply hitting Shift + G. Now all you have to do is click and drag over your image as you would to apply a normal gradient and you’re good to go – see the quick results in the animated gif image to the right.
If you’re experiencing the same issue, it’s easily fixed. When you save your Illustrator file as an .ai file, make sure you have the Create PDF Compatible File box checked.