Photo collage in PE 4

T3
Posted By
Treve_3
Dec 19, 2005
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684
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I like to make a photo collage (serveral pictures in a 50*75 cm print). I opened a canvas with these dimensions, imported with the place command the – 6 MP Nikon d50 pictues in separate layers and scaled them each to appr. 10*15 cm.

I don’t know whats wrong, but it seems that the scaled pictures become blurry; do I loose pixels during scaling?

Evert
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How to Master Sharpening in Photoshop

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JE
jim evans
Dec 19, 2005
On 19 Dec 2005 13:18:37 -0800, ""
wrote:

I like to make a photo collage (serveral pictures in a 50*75 cm print). I opened a canvas with these dimensions, imported with the place command the – 6 MP Nikon d50 pictues in separate layers and scaled them each to appr. 10*15 cm.

I don’t know whats wrong, but it seems that the scaled pictures become blurry; do I loose pixels during scaling?

Did you scale up or scale down in size?

jim
SG
Scott Glasgow
Dec 20, 2005
wrote:
I like to make a photo collage (serveral pictures in a 50*75 cm print). I opened a canvas with these dimensions, imported with the place command the – 6 MP Nikon d50 pictues in separate layers and scaled them each to appr. 10*15 cm.

I don’t know whats wrong, but it seems that the scaled pictures become blurry; do I loose pixels during scaling?

Evert

You are working with a bitmap (raster image). The only format which is infintely scalable is vector format, which you will _not_ get from your camera. If you scale a bitmap image up, pixels must be added; you add pixels which do not exist in the original image. This is done through a selection of or a series of interpolation algorithms. If you scale a bitmap image down, pixels must be thrown away, and again this is done through some rather sophisticated, but limited, algorithms which try to guess which pixels can be discarded without affecting the image overmuch. They enjoy limited success. This is the nature of bitmapped images.

Cheers,
Scott
T3
Treve_3
Dec 20, 2005
jim evans schreef:

On 19 Dec 2005 13:18:37 -0800, ""
wrote:

I like to make a photo collage (serveral pictures in a 50*75 cm print). I opened a canvas with these dimensions, imported with the place command the – 6 MP Nikon d50 pictues in separate layers and scaled them each to appr. 10*15 cm.

I don’t know whats wrong, but it seems that the scaled pictures become blurry; do I loose pixels during scaling?

Did you scale up or scale down in size?

jim

I scaled only down.

Evert
T3
Treve_3
Dec 20, 2005
Scott,
Thanks for your explanation.
But, what is the difference if I print a 6 MP picture on a 10*15 cm format? IMO, this is also a resize to that format without throwing away pixels (only the PPI value rises).
In principle, the only thing I want to do is to print a 6 MP picture with 10*15 cm dimensions on 50*75 cm paper.

Evert
CK
Charles Kerekes
Dec 20, 2005
Evert,

But, what is the difference if I print a 6 MP picture on a 10*15 cm format?

The difference between printing in various sizes vs. scaling in PSE is this: when printing to a specific print size, the software doing the printing maintains the original number of pixels and the printer driver software interprets the image to the appropriate dots for the printer.

When scaling, the software adds or throws away pixels. Then, the image still has to go to the printer driver for more conversion. So, when you are scaling, more change occurs to the image before it hits the paper.

In principle, the only thing I want to do is to print a 6 MP picture with 10*15 cm dimensions on 50*75 cm paper.

Try this-forget the final measurement in cm’s while composing the collage. Take the original photos that you want in the collage and calculate the total pixels the final image (blank canvas) requires to hold the images. For example, lets say you want a collage of four images and each image has the following pixel dimensions: 10 x 20 (I’m using small numbers to make the math simple.)

If I want a 5 pixel margin all around the collage and between the images, the final canvas width needs to be 5 + 20 + 5 + 20 + 5 = 55 pixels. The height needs to be 5 + 10 + 5 + 10 + 5 = 35 pixels. Start out with a blank canvas size of 55 x 35 so that adding 10 x 20 images requires no scaling at all. To print it, adjust the printer paper size.

Hope this helps.

Charlie
http://FlyingSamPhoto.com
JE
jim evans
Dec 21, 2005
On 20 Dec 2005 01:11:38 -0800, ""
wrote:

jim evans schreef:

On 19 Dec 2005 13:18:37 -0800, ""
wrote:

I like to make a photo collage (serveral pictures in a 50*75 cm print). I opened a canvas with these dimensions, imported with the place command the – 6 MP Nikon d50 pictues in separate layers and scaled them each to appr. 10*15 cm.

I don’t know whats wrong, but it seems that the scaled pictures become blurry; do I loose pixels during scaling?

Did you scale up or scale down in size?

jim

I scaled only down.

Well, yes you lose pixels when scaling down but with a good scaling algorithm such as bicubic you should still get an excellent image.

I recently made a poster about the size you are doing that contained 4×6 images (pretend snapshots) sprinkled around on it.

Here’s a JPEG of it http://tinyurl.com/c6mmv

Each image was started out as 8 MP. Since the main quilt images were also 8 MP, in order to get these relative sizes I had to resize "snapshots" to about half. In the final poster the snapshots were as sharp as if they had been printed independently retaining their full pixel content.

If you don’t downsample your 6 MP image more than about 40% you should get good quality results.

After you downsample, what resolution in ppi (pixels per inch) are you getting?

Are you sharpening each of the 4x6s, or merging the layers and sharpening the overall image?

While writing this it dawned on me what you may be doing wrong. When you say "I opened a canvas with these dimensions," what was the resolution (ppi) of this canvas?

Also you didn’t say how many 4×6 images you’re putting on this 30 inch tall canvas and if you’re covering the canvas with them or leaving space for other things.

With all it’s layers, the image I linked to above was pushing 500 meg. I only have one gig of memory each procedure I applied to the image took a looooong time to execute on a file this large.

I have to wonder if you didn’t create a low resolution canvas and down sampled your individual images to this low resolution.

To figure out the final resolution of your individual images try resizing them before you add them to the canvas. This will require a little trial and error until you get the size about right when it’s put on the canvas but it only has to be close. Once you’ve done that, go into Image Size, uncheck the Resample Image box and change the dimensions of the image to 10×15 cm (4×6 inches). Then read the resolution value. If it’s much below 200 ppi (80 pixels per cm) that’s your problem.

jim
___
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JE
jim evans
Dec 21, 2005
On Wed, 21 Dec 2005 00:30:35 -0600, jim evans
wrote:

To figure out the final resolution of your individual images try resizing them before you add them to the canvas. This will require a little trial and error until you get the size about right when it’s put on the canvas but it only has to be close. Once you’ve done that, go into Image Size, uncheck the Resample Image box and change the dimensions of the image to 10×15 cm (4×6 inches). Then read the resolution value. If it’s much below 200 ppi (80 pixels per cm) that’s your problem.

I had a momentary brain blowout. All you need to do is apply the procedure described above to your final/composit image. To restate it for the composite image:

Go into Image Size, uncheck the ‘Resample Image’ box and change the dimensions of the image to 50×75 cm (20×30 inches) — which they probably already are given your description. Then read the resolution value. If it’s much below 200 ppi (80 pixels per cm) that’s your problem.

jim
T3
Treve_3
Dec 21, 2005
Hi Jim,
As a matter of fact, I made such a collage first in CorelDraw by importing the 6MP pictures and resize them in CorelDraw. All pictures were sharpened and improved for level and contrast in PS before. I imported appr. 25 pictures (!) and there was no space between the pictures (but overlap). When I sended the JPEG (19 MB, appr. 7000*5000 pixels) to the printshop, the result was quite unsharp (soft). The JPEG itself on the screen is as sharp as all the individual pictures and in PS it shows 300 dpi with 7000*5000 pixels. I thought the softness on the posterprint was caused by CorelDraw, because the print of another printshop was also soft.

So I tried is with PS the way I explained before with a couple of pictures, but then it was soft already on the screen. Besides this, I doubt if it is possible to import 25 pictures in PS without getting a tremendous filesize and performance problems.

Evert
JE
jim evans
Dec 21, 2005
On 21 Dec 2005 02:48:24 -0800, ""
wrote:

PS it shows 300 dpi with 7000*5000 pixels.

Unless I’ve made another bonehead mistake 7000×5000 pixels printed at 75×50 cm would yield about 240 ppi or 95 pixels/cm. Still, this should be adequate to produce an image that’s not obviously blurry.

I’m running out of guesses on why you’re having your problem.

jim

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.

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