How to reduce an image size

[ogee]

I have downloaded a large number of professionally scanned pages from old newspapers and the files are huge (5MB+)...I would like to share a large number of them but want to lessen the file size as well as highlight passages on each page without increasing the file size. I also want to be able to print them on 81/2x11 inch paper without losing detail...how do I go about doing this?
Example: [URL=http://i883.photobucket.com/albums/ac36/ontgen/Newspaper/DixonEveningTelegraphDixonIllinois18-Copy_zpsc817cdcd.jpg[/URL]

[Tony W]

Re: How to reduce an image size

First 5Mb is hardly a huge file size, but they could probably be reduced to around 1/3 of that size.

The pages have been scanned as colour images therefore assuming all are standard B&W newsprint then converting them to grayscale using PS Image / Mode /Grayscale will give the much smaller file you seek.

Obviously the link that you posted has been reduced as it is approx 2.3 MB as an RGB image and when converted to grayscale reduces to 784 KB.

You will need to be careful not to try and resize too small if the smallest print is going to be readable - as it is your link copy is for me at least not readable

[ogee]

Re: How to reduce an image size

Thanks Tony W.
No idea what happened when I up loaded the image to Photobucket...first time for using it, and it seems to have reduced the image from 5.1 MB and made it unreadable.
I will try converting a copy of the original to gray scale and working with that.

[ogee]

Re: How to reduce an image size

When I go to Image/Mode/Grayscale it increases the file size not reduces it....working on a copy of original not the linked version.

[Shoku]

Re: How to reduce an image size

When I go to Image/Mode/Grayscale it increases the file size not reduces it....working on a copy of original not the linked version.

That's impossible if you are going form RGB to greyscale. Three channels will always be larger than one. You must be reading the size wrong? 2.65MB file in RGB changes to 677.9KB after color space conversion with no change in resolution

[Tony W]

Re: How to reduce an image size

Agree that it is not possible to go larger when converting RGB to Grayscale so you must have changed resolution by resampling.

An example an RGB file with 1600x1200 pixels will give a file size of 5.49MB. Convert this to grayscale and the size will reduce to 1.83MB.

But if you have changed anything in the document size panel and set to Resample image the file size will change.

[0lBaldy]

Re: How to reduce an image size

You might try...

To get it on a 8.5X11 for printing:

Opened a new document in PS... 8.5X11, 300 Res, Greyscale
(or Preset> U.S. Paper, Color mode> Greyscale)
Advanced> Dot Gain 30%
File>Place> (Your Document) (it will be placed into the new document and in FreeTransform.. just double click or click the FreeTransform Check mark to set in place.)
A Levels Adjustment layer will help a lot (Bring the black side to about 180)

To share: New document in PS... 8.5X11, 180 Res, Greyscale (and the rest of the above)

Then Save for Web & Device (Alt+Shft+Ctrl+S) to reduce file size

You should be able to share like this.. http://www.pixentral.com/show.php?pi...VylZrDVYgMmZT1

[ogee]

Re: How to reduce an image size

Thanks everyone for the help...I'm still trying to find out why my file increased instead of decreased in size, but have suddenly got busy with something else...Thanks OlBaldy for your suggestion and I will try it when I get a block of time to mess around.

[girlsfather]

Re: How to reduce an image size

jpgs are already compressed.

The greyscale conversion will not do that much to reduce filesize here.
(different story in uncompressed Tiff, uncompressed PSD ..)
But saving with a lower setting of the quality in the save dialogue box can bring the 20.3 MB jpg (that says 27.8 when saving as greyscale with maximum quality set in the dialoguebox) down to 5.7MB at 0% quality - that still is good readable.

zipping the file reduced another 10% in this case.
This ZIP archive you have to try - sometimes it is more, sometimes less.
The only way to reduce further is to resize.

[Tony W]

Re: How to reduce an image size

Good points about Jpeg size. I am that used to thinking in terms of psd or layered Tiff that I forget there are compressed alternatives out there.

So images shared will benefit being Jpeg as you will not generally need to send out a layered file - save these for your editing only and then if file size is an issue convert to greyscale