I have to put some new forms on our intranet. The current ones are either word documents or image (TIFF) files. They are in the order of 30-50kB.

The new forms were faxed to us. I've scanned them in and came out with 300dpi TIFF files via the scanner and they're weighing in around 25MB!!!

I've tried:

- greyscale the image
- reduce dpi to 150
- gone for LZW compression when saving as TIFF files.

All of this has brought it down to 6MB which is still too much. Even JPGs can only get the image down to 500kB. Any more ideas on (ideally lossless) compression?

The other scanned forms are in a similar pixel size eg 1200x1700 pixels and 150dpi.

Ask the form suppliers to email you PDFs instead. Those should be very small.

Have you scanned them at 8-bit or 16-bit per pixel? Drop down to 8-bit. Also check that your image editing software is saving the TFF using LZW (or similar) compression.

Also, if faxed, there may be a lot of noise in the image that may not be obvious, but will add to the size of the file. Scanning will compound that.

Unable to get the original docs but will get the secretaries to have a bash. The forms are NHS referral forms.

I managed to get the images down to below 50kB by doing the above, saving the images and then using the Save As Web option in photoshop to heavily compress the images.

Scanning as bitmap images would be the way to go on this.

Does your scanner not allow the scanning of documents into PDF format?

If not PM me as you could perhaps email them to me at work, I could scan them as PDF's and email them back.

Yep, agreed. As it's already been faxed there are only two colours - black and white. Scanning as greyscale just increases the amount of data as there aren't 256 shades of grey in the original, so it's effectively a bitmap anyway.

Faxes need to die.

Generally, I would use Paint or Gimp to re-size the images to something sensible that you can still read easily, perhaps 1000 pixels width. Then save as PNG

PNG is nearly always the best compromise for text.

+1

Not when computers, scanners and software can and will throw a wobbly with something time-dependant

I'll have another look at this option.


Yes it does. I don't know what the file size would be nor the quality of images but happy to have a go.


Except our cancer referrals are done via forms that I print off the intranet, fill in and then fax off to the referral centre.


The form, albeit an image, still needs to print full sized on an A4 sheet of paper. It needs to be fairly foolproof as we have technophobes in the building. What I did was decrease the dpi. Certainly saving as 2-colour PNGs made a big difference.

PDF is just a container. What it will hold are bitmaps (TIFF, PNG or JPEG) to the page size (A4 - likely at 150ppi), and the file size will bloat accordingly.

A PDF, when done properly, will contain the font, the text which will be displayed in that font, and supporting bitmaps and vector line art. If your form was a PDF which contained just the text, the font (or the subset of characters used in the document) and any vector line art, it will be much, much smaller. Scanning to PDF would only work satisfactorily if your scanner software was clever with OCR and discarded the bitmap when it was finished. Otherwise, yes, you will get huge file and, yes, you will, have to compromise on legibility if you wanted to keep the file size down. Scanning to PDF is like taking a screen shot and embedding it in a spreadsheet.

PDF does have the advantage of being idiot proof. I'd often embed the PNG image into one, so it printed A4 with no effort at the receiving end.

Same here. It's just that a file is not smaller by virtue of being a PDF. You still have to compress the image t before wrapping it in a nice warm fuzzy idiot proof jacket (With velcro, as opposed to a zip or buttons) though.