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Resizing Imagery


#1
Hi Guys,

Can anyone shed some light on resizing imagery through photoshop?

I have got a lot of imagery for a catalogue i am putting together yet a lot of the imagery is small in size and resolution.

I know i can change the resolution through photoshop via image size, changing the dpi to 300, keeping resample box ticked.

However the problem is where i want to increase the dimensions of an image to make double page spreads etc..

Is it just a case of amending the dimensions and away we go, or is there anything i should be aware of?

Any help on this thread, truly appreciated...
 

bigdave

Moderator
Staff member
#2
The long and short of it is that you can't add what isn't there!!

You can change an image from 100dpi (dots per inch) to 300dpi but all you've really done is either split one dot if colour into 3 dots of that same colour or have reduced the original image by a third. Either way, the resulting image will scale at the samd rate as the original dot would so there will be no visual improvement.
 
#3
Can I get away with increasing images for print then as long as the resolution is increased, I have images from a client that are too small for an a4 spread or double spread but will work on a visual level perfectly if I can increase them to fit?

If the method mentioned above via photoshop will not work, do you know of another?

Once again thanks...
 

@GCarlD

Well-Known Member
#4
Can I get away with increasing images for print then as long as the resolution is increased, I have images from a client that are too small for an a4 spread or double spread but will work on a visual level perfectly if I can increase them to fit?

If the method mentioned above via photoshop will not work, do you know of another?

Once again thanks...
Basically if the image you want to use to too small and low res for an A4 spread then its too small and low res for an A4 spread. There's nothing you can do about it. Increasing the size of low res images will only make it blurry and pixelated. You need the original image to be of a high enough res for what you require it for. It's always better to have an image that is too big rather than too small for this very reason. You can shrink an image without losing its quality but you can't increase the size of an image without losing quality unless it already is a high resolution image.
 
#6
For Litho print 300 dpi is the recommended minimum. I'd say that adjusting them up in PS isnt really ideal. I was taught that you can downsample big images to 300 dpi at printed size (for very big images) but if you need more resolution you need a new high res pic!
 

bigdave

Moderator
Staff member
#7
Print resolution is 300dpi. So if you need to scale an image up by 100% it would need to be 600dpi to start with.

Easiest way to sort this it to create a new canvas in photoshop that's the size of your spread at 300dpi in CMYK. Open the image you want to use then drag & drop the image into your new canvas. The size the image displays at on the canvas is the maximum possible size for that image at print resolution. If you need to make it bigger it'll distort and so is no good. If you need to make it smaller then you're laughing!
 
#9
Have a look at Photozoom Pro 5 - while I don't find it brilliant for massive enlargements, it certainly is good for anything up to about A1; I think you can get it on trial for 30days. Essentially drop in your image in cmyk at 300dpi then type in the size you want and there are a few sliders / settings at the bottom to tweek
 
#10
Cheers Spotty,

I have nothing going bigger than A3 size, double A4 spread. The problems is that certain images are around A5 size and already at 300dpi.

I'll have a look at this photozoom now.
 
#11
word of warning, when you are re-sizing a cmyk image with Photozoom the colours look as messed up as hell but they are correct when you drop them into a document
 
#13
I Use this

Smilla Enlarger is a free photo enlarger which is quite good. Download SmillaEnlarger for Mac - Digital photo-enlarger produces sharp results (was ImageEnlarger). MacUpdate.com
As has been mentioned, you won't get a better enlargement from an image that doesn't have the detail in the first place. However, you may be able to do something creative to help. :thumb:

Hi I use Perfect Resize 7.5 Pro, i downloaded a trial, have used it to produce some large panels with images that where to small.