Dropping "noise" from bitmapped images

JD
Posted By
Jamison_Delane
May 25, 2004
Views
202
Replies
12
Status
Closed
Hi,

I scanned a bunch of forms and before I scanned them all, I opened the first one in Photoshop and it looked good. However, when I import them into Quark, it is obvious that they are too dark because the rules spread and there is some background "noise".

In the past, I have been able to convert them to grayscale in Photoshop, adjust them by using <levels>, convert them back to bitmap and they have printed well.

However, after adjusting them on the screen and clicking <OK>, when the screen is refreshed they revert to their old appearance and print the same way.

I am on a new computer and possibly I’ve overlooked some settings.

Any leads would surely be appreciated.

Thank you,
Jamie
Related Tags
bitmap dropper image noise

Master Retouching Hair

Learn how to rescue details, remove flyaways, add volume, and enhance the definition of hair in any photo. We break down every tool and technique in Photoshop to get picture-perfect hair, every time.

RG
Rene_Garneau
May 25, 2004
What resolution are the images at?

You are printing to a Postscipt Printer?
MA
Michael_Allebach
May 25, 2004
If you are judging your image by the screen and it looks jagged in Quark, make sure you saved your image as a tiff not eps. Eps will appear jagged in Quark but will print fine.
JD
Jamison_Delane
May 25, 2004
It is line copy and I scanned it at 1200 dpi.
Yes, I am printing to a postscript printer.
By the way, the form prints well and the lines are not jagged, it is just that I apparently scanned them too dark and everything became too bold with some of the white background picking up as "dirt".
Is there a way of adjusting them by lowering the contrast? To reiterate, they seem to adjust after converting to grayscale, but when I hit <OK>, after processing, the screen redraws and they look and print the same way.

I’ve tried this in both Photoshop 5 and Photoshop 6 with the same results.

Thanks again,
Jamie
P
Phosphor
May 25, 2004
Can you post one of these documents (ZIP or Stuffit-compressed) where one might be able to download it?

The type and degree of "dirt" will determine the proper course of action. Trying to textually describe the type and extent of the dirt is not easy.

I’ll offer some advice if I can see a document, opened here on my system.
JD
Jamison_Delane
May 25, 2004
I emailed you a small section of the form because the file is very large. I thank you for any advice you can offer.
Jamie
P
Phosphor
May 25, 2004
OK Jamie…

I got your file. I can’t say whether this will work for all of your scans, but it worked quite well for the portion of the image you sent me.

First, change the Image Mode to Grayscale.

Now run Filter—»Noise—»Dust and Scratches… with settings of 4 pixel radius and Threshhold of 0.

This won’t get rid of ALL of the noisy dirt, but it’s a pretty good start.
JD
Jamison_Delane
May 25, 2004
What I tried before I received your response was converting to grayscale, selecting <FILTER> <OTHER>. I am not even sure what this filter is, but I put 999 in all the boxes, converted back to a bit map and the printed copy looks identical to the original.

Again, I thank you for your time…you guys are really great!!!!

Jamie
P
Phosphor
May 25, 2004
There are usually several filters under Filter—»Other…

Sounds like you used "Custom…", and have blindly stumbled onto something that works. I didn’t test it, so I can’t be sure. But if it worked for you, that’s great.

But, until you know how the "Custom…" filter works, you’d be better off using something similar to my suggestion where the visual feedback is available when you move the sliders. With the "Custom…" filter you’d just be guessing at what the results will be. If you need to make an adjustment to the intensity or quality of the effect that the "Custom…" filter produces, you’re gonna be lost.

This, being spoken by a long time user who is completely lost when trying to create my own custom filter convolution matrix.
R
Ram
May 25, 2004
Have you tried scanning at 300 ppi instead? You might just have too many pixels in your scanned images.
RW
Rene_Walling
May 25, 2004
Ramón,

For an image in bitmapped mode, 1200 ppi is about right.
R
Ram
May 25, 2004
Rene,

I didn’t say it wasn’t. I’m just asking if they’ve tried 300ppi or not.
AS
Ann_Shelbourne
May 25, 2004
The idea is to create the bitmap at the same resolution as the RIP so that it goes through dot-for-dot.

If you are less than happy with the quality of the Type, you might try setting that separately (using the scanned forms as a template).

The other thing that you might try is this Acrobat trick: Ann Shelbourne "OCR which actually works" 5/22/04 6:13pm </cgi-bin/webx?14>

However, I have not tried it on a form.

How to Master Sharpening in Photoshop

Give your photos a professional finish with sharpening in Photoshop. Learn to enhance details, create contrast, and prepare your images for print, web, and social media.

Related Discussion Topics

Nice and short text about related topics in discussion sections