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Image Transparency

August 06 2010 | 0 comments
Categories: ArcGIS Methods, Map Elements, Page Layout

I am trying to create a collage of photos which are all sort of faded to white. On top of the collage I want to have our city logo in full color. I have attached an image showing what I mean. In the attachment there is only one image right now, but imagine that entire white space filled with the photos faded to white, then the logo on top. Is there a way to make the logo's white background transparent? Thank you for your help.

Mapping Center Answer:

There are a couple of ways to do this.  The easiest is perhaps the least obvious, which is to not use inserted graphics in your layout.  Instead, use a data frame that you'd call "Logo", and then add your logo image and your photos.  In your logo image, set the background color (on the raster layer properties' symbology tab) to be white (same RGB value as your logo image).  Then you can also adjust the transparency and drawing order of the photos using the TOC and layer properties.

The one trick to making that work is to use the Georeferencing Toolbar--where you will zoom to an extent you want your logo or photo to be located, and select that image layer in the Georeferencing Toolbar's drop-down list of image layers, and then from the Georeferencing menu, choose Fit to Display.

The other way to do this, in layout view, will involve editing your image files--For your logo you will need to use a .GIF format image.  You will need graphic image editing software, and you will need to use the function in that software that allows you to set which color should be fully transparent.

One caveat on the first method--you won't be able to get away with putting just your logo image in a data frame and setting it's background color to "No Color".  The issue is that while on screen it will look okay, data frames do not support transparent backgrounds--their background is white.

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