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transparency in background for a tif

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#1
araki5

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hi all. i am trying to export a tif for a figure to be used in excel. i have the figure as a 300dpi tif that is 4x4in.(about half a page of letter).

so, is there an easy-quick-n-dirty way to "transparentize" the background? it' really tough for me to use the lasso/magnetic tools. i am using photoshop 6.0 to do the tif manipulations.


be advised, i am exporting out of autocad map 3d.

thx all.
Randy Long
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Raster is Faster, but Vector is Corrector.

#2
benbakelaar

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Good luck if someone knows, but here is what Wikipedia says:

""
PNG and TIFF also allows partial transparency, which solves the edge limitation problem. However, support is even more patchy. Internet Explorer prior to version 7 does not support partial transparency in a PNG graphic. Very few applications correctly process TIFF files with alpha channels.

http://en.wikipedia....rency_(graphic)
""

So even if you get the export options right, I'm not so confident MS Excel will display it properly. A workaround might be to load the file in MS Word (using whatever format - BMP, JPEG, etc.), use the Picture toolbar (or is it Graphics?) to "click" the color you want transparent, and then copy/paste from MS Word.

#3
CHART

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Ben... is correct tif transparency is best managed by an application. So for example in MapInfo you set the transparency of a tif with the application. So not sure if AutoCad can set the transparency color.
Chart

#4
Matthew Hampton

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I haven't had any luck at all working with transparency and the tiff format. Both PNG and GIF should work fine.

I just checked and was able to Insert-->Picture from file... both a transparent PNG and GIF into Excel. I saved the same file as a TIF and had not luck.

In any case you need to take the tiff and delete the background color in Photoshop (magic wand). Even if Autocad had a GIF or PNG export - I doubt it would handle transparency.

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#5
araki5

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hi all. i think i found a solution.

i open up the dwg file i want to export. when i choose export options, i select .wmf. I forgot that when you do that, it will automatically transparentize the white background. not only that, the line work and text is very sharp for such a small exhibit on excel. i can insert image directly inside excel.

it's basically a vector format(who cares) and it seems to print just fine.

thx for the help guys.
Randy Long
GIS/CAD Tech
Mackay and Somps



Raster is Faster, but Vector is Corrector.

#6
Eva

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Randy,

I see you found the answer to your question, but just wanted to give you a tip on using photoshop. If you use the magic wand instead of the lasso it does not matter how steady your hand is. You can play with the tolerance (I have dropped it as low as 0 to get it to capture the image properly) and then just draw a circle encompassing the image and it will snap to your image. You can edit the line by using the shift and alt keys to add or subtract from the line and you can use the feathering tool to smooth the edges if your line is off by a few pixels. I hope that helps in the future. Maybe you will have some insight to my problem listed below:

I am currently trying to figure a way to create a tif with a transparent background. I am then using dmagic to convert the tif to a kml (or kmz) for input to google earth. I first tried in gimp, but had to save as a .png which can be manually georeferenced in dmagic, but will not export to kml. Photoshop allows me to save as a tif with a transparent background, but becomes too large for dmagic to handle and when I compress it dmagic fails or says it cannot read the georeferencing (coordinate system is assumed). I have tried arcmap, and can make the background transparent within the program, but it will not export as transparent. I am now looking into autocad to see if I can make a resonably sized tif image with a transparent background that will export to kml. If anybody has succesfully done this (or determined it impossible) I would greatly appreciate your input!

Thanks much,

Eva




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