Scanning Drawings

Hi All,

Can anyone tell me the best file format to use when scanning drawings. I have recently had some large and small drawings of a ship scanned and as JPG files and found that some of the files were corrupted in some way. They opened ok but I could not manipulate them in any way. The size of the file did not seem to be relevant but I wondered if perhaps a TIF format, or maybe some other, would have been a better choice. Can anyone offer advice?

Regards,

John

What do you mean by "manipulate them"?

You're inserting them into Autocad? What are you trying to do with them?

By manipulate the file I mean to convert it from colour to grayscale, or to BW, to rotate it and so forth. Or to converter from JPG to TIFF etc. In fact I find that the only thing I can do is to open the file and view it, then close it. I can do nothing else with it.

Wait a minute. Lets first figure out exactly who you are. Are you Jecobin or are you Boatman? Why are you signed up under two different names? Please let me know which name you would prefer to stick with so we can delete the other account.

As for the image, I assume you are inserting it in Autocad?

Autocad cannot convert the image from color to grayscale or convert from jpg to tiff or any other image editing procedures. The only thing you can do with an image in Autocad is view it. If you want to perform these other manipulations, you need to use Photoshop, or another image editing program.

Sorry about the name confusion. I used my son's account to quickly reply. If you would like to delete one account then delete Boatman - My son - and we will both use this account Jecobin.

The scanned images may or may not be use in AutoCAD but I am not trying to manipulate them in AutoCAD. I realize that this cannot be done in AutoCAD. I have simply found that on occasions when scanning a drawing I get the described problem where the JPG image opens but nothing more can be done with it. The size of the image does not seem to matter as it happens with both large and small. But I wondered about the file format as I normally scan my drawings to a JPG file. Maybe this is a bad choice?

You will need to use a photo editing program to convert to gray scale, then you will be able to use "save as" to a different file formats.

You will be able to edit the photo with in the program also.

There ars some programs available to convert the .jpg, .tiff file formats to a .dfx format that is editable in AutoCad.

HTH

I use the TIF image format start to finish. I have a local blueprint place scan the plan at about 200-250 DPI in TIF format, and write their efforts to my CD-rom disk. That costs about $3 each off their OCE' machine.

They can write in PDF or JPEG formats all the same, but the Jpeg image is distortion bound. The PDF is OK, provided that the lines and text were originally drawn via some CAD system. I assume someone here knows why the Jpeg turns out so poorly.

Then, I use the freeware WinTopo to reduce my scanned plan into little bits, and begin the Autocad connections, and erasures. Making the file go smaller and smaller K-wise. The software will divide the colours up, but mine plans are generally B&W and half-tones so who cares.

Wm.

Hi HTH, Yes I have already used image-editing software such as Adobe CS4 and an old app, HiJaak Pro. which I use a lot but neither is able to do and then save any changes to the images that seem to have the problem. If I do a 'save as' the file produced is corrupted and will not even open regardless of the format I chose.

I have been told since my last post that the problem can actually be the JPG file format. Apparently it is advised not to scan to the JPG format as its compression discards information that it feels it does not need. This can cause the problem I have encountered. It seems that it is advised to scan to a TIF file format as this keeps all information and discards nothing. From the TIF you can then 'save as' a JPG if desired. I have to admit that the problem has only even occurred with JPG files created by scanning. Perhaps this is the answer.

Coosbaylumber - I think I agree with you and TIF is the better way to go. I have never encountered any problems with TIF files and I think I made a mistake to scan to JPG.

One thing you touched upon, and needs mentioning.

That of image compression. I get different results if the image is compressed or not. Generally a compressed image will come out fine in an E-W direction, but distorted maybe + or - 5 percent in the N-S direction.

Near zero on an uncompressed file. I now generally uncompress the file, d the processing, and then bleep off the computer (days later) once done.

Wm.

Sorry about the name confusion. I used my son's account to quickly reply. If you would like to delete one account then delete Boatman - My son - and we will both use this account Jecobin.

Ok, it's not a problem if your son has one account and you have a different one. In fact, it's preferred. But in order to eliminate confusion in the future, please let your son use his account and you use yours.

You should always scan to tiff so that you have an original copy with all the image information included. But for inserting into Autocad, I always "save as" jpg format in order to reduce the file size which keeps my drawing files from becoming bloated due to the large tiff files.

As for the image problem, can you upload one of them for us to check out? I work with image files every day and have never come across the problems you're describing.

Format Advantages Disadvantages

BMP Almost none, maybe: general availability on the Windows platforms very inappropriate format, do not use; format is not compressed - resulting file is unnecessarily large

GIF Efficient, compressed lossless format, suitable for transferring screen captures, CAD data, maps, schematics, logos, etc.; transparency option 8-bit color depth, limited palette of 256 colors -

do not use for renderings and photos

JPG Very efficient, well compressed lossy truecolor format, well suited for transferring photographs and pictures where a loss of some pixels is not important lossy compression, makes artefacts in the picture,

blurs edges - do not use for CAD data

PNG Combines the advantages of GIF and JPG, compressed truecolor format, well suited for transferring accurate images, including CAD data, features alpha-channel (transparency) not so efficient format in

terms of the file size

TIF Compressible format for professional use - maps, scanned drawings, suitable for CAD and GIS data (monochrome and color) too many variants and sub-types, not all of them fully supported; not so widespread

I dunno about your file sizes, for yesterday got to working upon an Un-compressed TIF file that became 157 Meg upon insertion in to Autocad. Odd size, but is finally smaller now too. Can work faster with the smaller files then. I have worked with 400+ file sizes but the work awfully slow, and takes two days of in and out to get down to the 157 size too.

Wm.

Tankman – Thank you for the file format information. That’s well worth keeping a copy of and very interesting about the JPG format. I would be very interested to know which ones you use for various aspects of your work. I think I really did the wrong thing but at least I have a better ideal now.

Wm – My reason for using JPG in the first place was actually to keep file size down and speed up but I think that was the mistake. In the future I think I will scan to TIF and keep these files as the master copy and then produce working files from these masters as and when required and for whatever purpose I need them. I know the file size will be an issue when it comes to storage but at least I have a master that has all image information stored in it and a source for faster work files. The only worry is the TIF variants and sub-types mentioned by Tankman.

I do prefer the *.jpg images, smaller in size.

I usually dump the image after working on it, sometimes I don't.