Yes, I do, even if it doesn’t sound like it. By decreasing the size and increasing the ppi, I’m increasing the sharpness of the image and the quality of the printed version. I realize you can’t add information. It’s like the difference between watching your TV from 10’ and watching it from 10". The picture sharpness appears better from 10’.
Once a picture is taken, you can decrease the visual dimensions of the displayed image (from 8x11 to 4x6, for example), yes. However, you cannot tell the computer to increase the ppi from 200 to 300. That has to be done on the camera BEFORE the picture is taken – cf: Quartz’s comments.
What you’re talking about is, at bottom, just shrinking the displayed image to fudge the blurriness from lack of detail and make it appear sharper because it’s too tiny for us to see the blur. This is described accurately by the term “decreasing the size” and somewhat argumentatively so by the term “increasing the sharpness”.
Unfortunately it’s the middle part of that statement where things fall over. Using the term “increasing the ppi” to describe this act is misleading and technically inaccurate because this is not the part of the process where you can do anything regarding ppi. It ends up sounding odd to people who are more familiar with image processing, even if it seems like a convienent way to word the concept.
Does this help? From where I’m sitting, it seems to be more an issue with semantics.
No you’re not. As I said before, digital files do NOT have a physical size (in inches).
Making the picture file smaller will not make it “sharper”. Printing it smaller, or zooming out on screen, might, but only if you were originally printing or viewing it at a size beyond what the original resolution was capable of.
You said the images are going to be printed in a brochure, right? Well the DPI issue is purely and simply a matter for the printer. Adjusting the “ppi” settings in a graphics editor will do precisely nothing. Reducing the size (in pixels) will be worse than nothing - it will reduce the quality of the printed image.
Seriously, all you need to do is send your original, full-size files. It may be that they are not big enough to print at the required size at 300dpi, in which case you might get away with “upsampling”, that is increasing the size by a factor of maybe 1.5x. This would add pixels, but of course they would be interpolated and so not really improve the resolution.
But you are still confusing print size with file size. You do NOT have to edit the file in order to print it smaller. All you do is set the print size on your printer (or resize the image in whatever program the finished brochure is being created in).
Say I have an 1800 x 1200 file. I can print it at 18" x 12", in which case it will only be printed at 100dpi and will probably look rather pixellated. Or I can print it at 6" x 3", which will give me 300dpi and should look good. Or I can print it at any size in between, or even 3" x 1.5", which will be 600dpi but probably too small to see clearly anyway.
But all of these sizes can be printed from the SAME file, with no need to resize it, adjust the “ppi” or anything.
Yes, I am. Let’s stick to the facts here. If you want to dump on me, open a Pit thread.
Your posts do not make it absolutely clear that you do understand everything and IMHO you are being unfair to someone who is trying to help you. Maybe you do understand, maybe you think you do and you don’t, but there’s no need to be rude to someone who is only trying to help you.
I wasn’t trying to get personal at all.
My statement “No you’re not” was a factual reply to what you said:
because that is not what you are doing at all. Decreasing the size of a digital image file will not increase its sharpness or quality when printed.
Printing the image at a smaller size will give better quality results than printing at a larger size if the larger size is too big for the resolution of the image. But you don’t have to alter any size or ppi settings whatsoever in the source file in order to print it smaller.
All I’m trying to tell you is that you should ignore ppi and dpi, and just send the full-resolution files to the printer, and let him worry about what dpi it will be printed at. Whatever the size of your image is in pixels, divided those numbers by 300 and that’s the biggest you can print at 300dpi original resolution. Increasing the ppi setting of the digital file won’t make a jot of difference - it certainly won’t make it “sharper”.
I apologise if I came across as rude, but I am trying to explain where you are going wrong.
Here’s an example:
Say you have a file that is 2560 x 1920 pixels, which is a typical output from a 5mp camera.
You look at the properties of the image, and it tells you that the file has the following dimensions:
Width: 35.56"
Height: 26.67"
Resolution: 72ppi
That means that if you view it on a 72ppi monitor at 100%, it will be almost 3 feet wide. At 100% zoom, you will only be able to see a fraction of it on your monitor.
But you want to change it to 300ppi. So you change the resolution to 300ppi, and now the dimensions show the following:
Width: 8.53"
Height: 6.40"
Resolution: 300ppi.
Now the “full size” picture is only 8 and a half inches across.
BUT, this is the important bit: the image is IDENTICAL. It still has the same number of pixels. You haven’t lost or gained any resolution. All that has changed is the divisor the program uses to go from pixels to inches.
You can still print the “72ppi” file at 8.5" across and have it print at 300dpi. You can still print the “300ppi” file three feet across (if you have a big enough printer) and see the low quality.
Whoever you are sending the files to will not even look at the ppi value. All that matters to the printer is the number of pixels.
Ugh. No, lol.
JPEGs a lossy format, so technically it doesn’t have a dpi or a ppi. The picture is stored as data, run through a number or algorithms (type and number depend on your camera and the amount of compression (the “photo quality” you’re using)), and stored. Then it’s run through the same algorithms in reverse to view or print the photo later. This allows website folks to use a large image but box it into a smaller space without having to edit the photo itself, for example. It’s why some programs open the thing in a huge window, while others open a smaller window. Most formats work this way, but being lossy allows JPEGs to scale a bit faster and easier, although quality can still bite.
So really, you’re just messing with the EXIF metadata (64kb of data), not the image itself. If you’re the really bored type, you can google exif editors and grab a calculator, and do this on your own, without any “real” photo editing software.
That doesn’t really help though, does it?
Alright, easy way in gimp, load your picture, go to image -->scale image. You can set both your dpi to make your image 600 dpi so the guy printing it is happy, and also allow you to adjust your X and Y sizes as desired so they fit nicely on the brochure. Of course, it works better if you take the photos in a higher quality format, and store them in a tiff or raw format (huge files!). As other’s shock has shown, printing with JPEGs can be a little dicey, and for anything professional, best avoided. They’re great for internet usage and back in the day when a few jpegs ate serious hard drive space, but it’s much less an issue today.
Just to clarify…there are two ways to “change” the dimensions of a pic. One is to modify the specs, as I believe you are describing, while keeping the number of pixels in the image unchanged. This will not alter any image data, but it can affect how it displays or prints.[sup]*[/sup]
The formula is (pixels per inch) = (number of pixels) / (inches), so if you want to double the (pixels per inch), you have to halve the (inches) or double the (number of pixels) to keep from altering the image.
Or you can resample, which involves interpolation of pixels, and will alter the image data by adding, subtracting or modifying pixels.
There are advantages and uses for each method.
[sup]*[/sup]This is less true today since outputs are usually directed thru image-altering control software, but long ago and in simplier days, the rule of thumb was if you send an image to the screen raw, one file pixel was mapped to one screen pixel, but if you send it to the printer, the dimension in inches was the parameter that was used for the print size.
This is incorrect. JPEG is a compression scheme but the compressed graphic has a definite dimension in pixels and a JPEG-compressed graphic does indeed have a field for DPI which you can see and change in Irfanview.
On the other hand GIF AFAIK does not have a DPI field which is one more reason to use PNG instead (Which is generally far superior anyway).
You know, sailor, I can’t help but notice that you keep saying dpi where you should be saying ppi, so I don’t know how much you’re actually helping (if John Mace even needs help, since it seems to me it’s all just a big misunderstanding). Half the “help” given in this thread is completely wrong, anyway, so even if he does need help he’ll have to find it somewhere else.
Except that it is a nitpick without a distinction or difference which has already been argued in other threads. Essentially DPI and PPi are used interchangeably. In fact DPI is the term used in practice in most graphic programs and you can open Irfanview and see it says DPI. So this is just silly nitpicking. If you have a problem with the term DPI you can go to the graphics programs and tell them so. I believe everything I have said until now is correct and I am very willing to be corrected if I have made any mistake but this is just silly. I have quite some experience with graphics and graphic formats but I am always willing to learn.
And if you believe half of what is said is wrong you would do well to correct it and not let it stand.
GIMP is OK but for a great free editor try
XNVIEW
This rocks. It can’t do everything GIMP does but for it’s size and the fact it’s free, between XNVIEW and MS Paint, you can do pretty much all you’ll need
I use a variety of tools and each one has its strong points but I find Irfanview to be the best and simplest for compression, format transformation etc.
MS Paint is terrible for this and it does not even let you change the DPI setting which IIRC is set at 96 DPI. I just do my work in Paint and then copy to Irfanview and do any final resizing, brightness and color adjustment, DPI etc there.
Irfanview compresses much better than Paint. It handles all common formats very well and lets you adjust many parameters. For PNG, GIF, JPEG, TIFF CCITT 4 and other formats Irfanview beats Paint hands down.
MS Paint is good for certain things like drawing an arrow or a circle or a line on a photo or for doing simple line drawings (I use it a lot for this). It is no good for any serious photo editing and it is very mediocre for compressing and saving.