What color compressed image file works

[raysmith8525]

What color compressed image file works within Autocad? Our scanners create a group 4 TIFF, which is not compatible with Autocad.
We would like to change the default setting on the scanners for an image file that does not need converting before it can be inserted into a drawing.
Does anyone know if “LZW” type works? (The format my IT guy wants to use)
We are currently running LDD 2009, Raster, Civil, and Survey

[Anonymous]

Seeing how Raster Design can create a LZW
compressed TIF I would think it works.

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"raysmith8525" wrote in message
href="news:6155622@discussion.autodesk.com">news:6155622@discussion.autodesk.com...

What
color compressed image file works within Autocad? Our scanners create a group
4 TIFF, which is not compatible with Autocad. We would like to change the
default setting on the scanners for an image file that does not need
converting before it can be inserted into a drawing. Does anyone know if “LZW”
type works? (The format my IT guy wants to use) We are currently running LDD
2009, Raster, Civil, and Survey

[Anonymous]

no, group 4 does work and is the best compression choice for bw tiff.
We have an OCE scanner that does CCITT group 4 all day and I use Corel Photo Paint to do that compression too.
I also have a .net tool that does group 4, all with no acad problems.
There is some other issue with the tifs.

I have researched this issue of what color format is best for server space and AutoCad, and have concluded a jpg with
30% compression is best.
You cannot create "color indexed" drawings with jpg, or transparent pixels. Use PNG for those situations.
Even if you take a 24 bit color jpg, and convert to 256 color optimized palette (known as an indexed palette), the jpg
will be smaller with 30% comp.

You can get super compression with ecw files, but must pay to get the converter for files over 80mb I think.
So we use tif with group 4 compression for bw, jpg for all else.

Be aware that jpg is a lossy format, while tif and png are not. The compression of jpg is so good because of this
lossyness, so don't save a jpg 5 times in a row at 30%. Keep at 0% compression til you are done.
I usually keep a png original, then save to jpg when done tweaking.

I wish someone out there had written a better manual on this, its taken years of experience to settle on the best
options given all the image flavors and compression issues.

raysmith8525 <>
|>What color compressed image file works within Autocad? Our scanners create a group 4 TIFF, which is not compatible with Autocad.
|>We would like to change the default setting on the scanners for an image file that does not need converting before it can be inserted into a drawing.
|>Does anyone know if “LZW” type works? (The format my IT guy wants to use)
|>We are currently running LDD 2009, Raster, Civil, and Survey
James Maeding
Civil Engineer and Programmer
jmaeding - at - hunsaker - dotcom

[MichelLoftus]

I generally use PNG for Black and White or images that use blocks of colour and JPEG for other images such as aerial photos.

The compression of the PNG images is much beter for images that contain block areas of colour such as many maps. Also you can create trasparent colour images using PNG that you can't do with JPEG.

[Anonymous]

png is not more compressed than the CCITT group 4 tif.
The transparent pixel is slick with png, but I just tried it in 2009 and its not working! Wonder if that was a feature.

Agree on png blocks of color, like with USGS maps.
A slick thing you can do with png is convert 24 bit color to indexed 256 color. jpg does not support that but png does.
I use Corel Photo Paint, but some oethers do the indexing thing too.
So you can really get compact png's for those map like files.


MichelLoftus <>
|>I generally use PNG for Black and White or images that use blocks of colour and JPEG for other images such as aerial photos.
|>
|>The compression of the PNG images is much beter for images that contain block areas of colour such as many maps. Also you can create trasparent colour images using PNG that you can't do with JPEG.
James Maeding
Civil Engineer and Programmer
jmaeding - at - hunsaker - dotcom

[Anonymous]

the transparent issue is my fault, because I cannot get it to work in 09 or 06 now.
I tried as 24 bit color and 8 bit paletted. Corel shows it correctly, but acad keeps the trans pixels white, even with
trans setting on.
James Maeding
Civil Engineer and Programmer
jmaeding - at - hunsaker - dotcom