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[DanTheMan]

Thanks for any help anyone can give me here. I'm pretty new to digital photography and even newer to Photoshop.

These pertain to some vacation pics I'm working on. I shot them in RAW with my 8mp Nikon 8800.

1)Why would I use any resolution other than 300ppi (or even better if possible)? If file size is the issue, I have lots of HD space.

2)What happens if I just convert my RAW pics to JPGs and send them out to be printed; will they resize them at a low ppi?

3)If I resize most of these to 4x6 and a few 8x10s and change my mind and decide to make a few of the 4x6s larger, can I just open them and resize them, without loss, or do I have to go back to my original saved pic? Sorry if that one is worded badly.

Thanks for any help...I'm slowly getting a grasp on the basics

[Medley]

OK, let's take these one at a time:

1)Why would I use any resolution other than 300ppi (or even better if possible)? If file size is the issue, I have lots of HD space.

File size is seldom the issue here. The native resolutions of most inkjet printers is around 300 dpi (that's 'dots per inch', not the same thing as pixels per inch (ppi) but they are related). However, the native resolution of Epson printers is around 360 dpi, and converting to 360 ppi will generally yield better results on an Epson. So, generally speaking, 300 ppi works well for most printers, and 360 ppi works marginally better for Epsons.

However, if you are making a very large (poster size or better) print, you can sometimes get away with less ppi. Why? Because the farther away your subject is from the print itself, the less resolution is needed to provide the illusion of continuous tone. And the larger the print, the farther the subject will naturally stand from it to view the image as a whole. Image content also plays a role- people will tend to stand farther away from a portrait, and move in on a cityscape to view the detail. there really is no magical formula- or if there is, I haven't found it yet. But I've printed large images at a resolution of 220 ppi and had them come out fine.

By far the most general use of lowering resolution comes when the image is meant for web, not print. Anything meant to be viewed on-screen is generally reduced to around 72 ppi. Screens resolutions can vary anywhere between 72 ppi and a little over 100 ppi, but 72 ppi is considered the norm.

2)What happens if I just convert my RAW pics to JPGs and send them out to be printed; will they resize them at a low ppi?

That depends on your printer, and the size you're printing the images at. Your Nikon 8800, set to it's maximum image size, creates digital images that are 3264x2448 pixels. So let's assume you're not using an Epson. the printer's native rsolution is about 300 dpi. If you tell it to print an photo that is 10 inches by 8 inches, its going to convert hthe image to about 3000 pixels by 2400 pixels. I'd be amazed if you noticed the difference. But if you tell it you want a 6x4 print, it will convert the image to around 1800x1200 pixels. Now, if you're lucky, it will just discard the pixels it doesn't need to get to the image size it wants. In this case it would discard about every other pixel. The place where this will make the biggest difference in your photo is at the high-contrast edges. If you've done any sharpening, you've just cut the width of your halos in half, significantly softening the image. And that perfect six-pixel feathering on the object you imported into your image just became a 3-pixel feathering job. I would say that this is what happens about 80-90% of the time, and it is definately noticable.

In the worst case scenario, the computer will attempt to put all the detail of your image into the smaller version. the result of this is the opposite of the first result, the edges look blocky and over-pixelated.

The solution for both of these conditions is simple: Decide ahead of time what size you want the print to be, and reduce the amount of pixels in the image to 300 times the size in inches- either by cropping the image, or by going to Image> Image Size to scale it down. Do this before you do any sharpening, so that the effects are not reduced along with the image.

3)If I resize most of these to 4x6 and a few 8x10s and change my mind and decide to make a few of the 4x6s larger, can I just open them and resize them, without loss, or do I have to go back to my original saved pic?

If you're letting the printer manipulate the images, then yes, just re-open the image and specify a different print size. The printer does not re-save the image after it changes its size, so you're essentially starting with the same file you had before.

However, if you decide to take my advice, then you'll need a separate file for each print size you want. I've learned to code this into the filename. For example, "squirrel1(5x7).jpg".

Does this make things more of a pain? Yes it does, no doubt about it. But once you get the hang of it, it takes about 45 seconds TOPS to change the image size, and the improvement in print quality is worth it to me.

When you get the hang of this, let me know and we'll discuss the other part of creating a great print- sharpening.

Hope this helps.

-Medley.

[DanTheMan]

Awesome! Just the answers I needed
Thanks!

[Tombothetominator]

Medley = The printing master!

[Medley]

You're quite welcome, Dan. And thank you tombo. I did spend quite a bit of time learning how to create the best print possible, and my prints have improved dramatically because of it. It just seems logical. Creating great images is the whole point of getting a digital camera, right?

-Medley.

[DanTheMan]

Ok, I'm back again with (hopefully) my last question regarding this stuff.

I'm resizing and converting these pics to submit to Photoworks in order to have them made into a book. I tried to find the answer on their site, so maybe someone here with experience can help me....I intend to have this book made with a mix of sizes (some as large as 8x10). How should I size my images for upload to their site? Should I reduce all of my RAW shots to 8x10 size when I convert to JPG then let their system size them down as necessary?
Sorry, I'm going crazy over these pics. It was a special trip and I really want to get these right.
Thanks!

[Medley]

Reducing each file to the size you want is far and away the best metod, but if you're going to be having muktiple sizes, then reduce each one to the size of the LARGEST print you will want.

Having the printer reduce them further causes a bit of quality loss, but having the printer (or Photoshop, for that matter) enlatge them causes massive quality loss!

Also, just as a curiosity, have you sharpened the images for print? Nothing says you have to, but you'll get better prints if you do. I'll be happy to show you my method. which creates very sharp prints, but first I need to know 2 things:

1) The width of your display, in inches. I DO NOT want the diagonal measurement (which most manufacturers advertise), just the width. The best way to find this is by getting out the ruler/tape measure. And I only want the width of the display, not the whole monitor.

2) All of the display resolutions available to your monitor: 1024x768, 1152x720, etc....

Let me know.

-Medley.

[DanTheMan]

Thanks again, Medley. I've having a photobook made for a friend so I'll reduce all my pics to the largest they'll fit on 1 page I suppose.

Does it matter if I resize them before or after converting to JPG?

I was going to sharpen these, yes. I'd love to see your method...any help I can get, I'm a total beginner.
I should probably sharpen before I convert to JPG, right?

My monitor apparently has a "native resolution of 1280 x 1024 (SXGA)" according to the specs here
And the display is 15" wide.

[Medley]

If by "converting to jpeg" you mean saving the file as a jpeg, then that should be the absolute last thing you do. When you save as a jpeg, the computer compresses the file to make it smaller. In doing so, it discards some information. If you save the file once as a jpeg, and then reopen it, you won't see any difference. But if you save it as a jpeg, open it later and make some changes, resave it as a jpeg... etc, pretty soon you will have discarded enough information that it becomes noticable. The general rule I live by is to save it as a psd (photoshop) file until you're done with all your changes, THEN save the final file as a jpeg.

Now, as to the sharpening, you'll want to resize the image before you sharpen it. The next thing you want to do is determine the screen resolution and view percentage to use. My formula is to take the width of the screen in inches, and multiply by 75 (I'll expalin the 'why' of 75 in a minute). In the case of your 15 inch monitor, that gives us 1125. Next, we want to search the available resolutions for the one closest to 1125 pixels wide. My monitor has a 1152x720 resolution available, and that's very close, so I'd recommend that one if you have it. Now open the file in Photoshop, and set the view to 25%.

Now, let's examine why we've set it up this way. On a 15 inch monitor, a width resolution of 1152 pixels gives us a screen resolution of 76.8 pixels/inch (as close as we can possibly come to our 75 pixels/inch target. At 25% view, we're seeing one pixel out of every four (that's how Photoshop gets the image to appear that size on the screen. So the effective resolution of the image on the screen is 76.8 times 4, or 307.2 pixels/inch.

Remember now, the native resolution of most printers is around 300 pixels/inch. This resolution, at this view percentage, gets the onscreen image as close as possible to that resolution. Therefore, the image you see onscreen is VERY close to what the print will look like. Now when you sharpen, you can see how the settings will affect the print.

We have one more obstacle to overcome. Photoshop, in sharpening an image, applies the most sharpening to the areas with the highest contrast, and the least sharpening to the areas with the lowest contrast. That is the exact opposite of the outcome we want. Here's how to fix it:

You already have the image open. Duplicate the background layer (Layer> New> Layer Via Copy or (cmd/ctrl+J)). highlight the top layer, and go to Layer> Layer Style> Blending Options. At the bottom of the dialog box, you'll see the "blend if:" sliders. Use these settings:



Now when we do our sharpening, the darkest edges (below 40) and lightest edges (above 215) will receive no sharpening. Between 40 and 65, and between 190 and 215, the sharpening will be graduated. Between 65 and 190, the sharpening will have full effect. This concentrates the sharpening in the midtones, which is exactly what we want.

All that's left is to do the sharpening itself. Make sure your working on the top layer, and go to Filter> Sharpen> Unsharp Mask. This command has three inputs: Amount, Radius, and Threshold. Threshold is about useless- there are much beter ways to control where the sharpening is applied, as illustrated above. I generally set the threshold to 1 pixel and leave it there.

Of the two controls that are left, Amount controls how much contrast is applied, and Radius controls how far back from the edge to apply the contrast. If you make the radius too wide, it can be seen by the eye on the print, and that's not good. If you don't make the radius wide enough, you don't get the maximum sharpness from the print.

Here's one of those important tips that I'm going to ask you to accept on faith: extensive testing (mostly trial-and-error) has shown me that sharpening halos that are 1/100th of an inch wide provide the best overall sharpening, and are still small enough not to be seen. When I sharpen, that's my goal: 1/100th of an inch. That's why it's SO important to take the printer's native resolution into account- so that the printer neither enlarges nor reduces the sharpening halos. That's why we resized the images to 300 ppi. At 300 ppi, a 3 pixel wide radius will give us what we want. Set the Radius value to 3 pixels.

The rest is easy. Adjust the Amount slider while watching the onscreen image. Make it sharp without looking blocky or pixelated. Remember, the image on the screen very closely relates to what the print will look like. When you're done, merge the layers and save.

In your case Dan, the printer is going to reduce some of your images to get the print size you want. This means that it's also going to reduce the sharpening halos, and the image will lose some of its sharpness. But they will still look considerably better than they would have if you hadn't done any sharpening.

I know that this has been long and fairly technical, but I hope it has helped explain why I did things the way that I did. Any questions? LOL.

-Medley.

[DanTheMan]

Wow. Seriously thank you for all the assistance. I got about halfway through that, and I think I've got it so far, but I've noticed one difference. Maybe this doesn't matter or maybe I have something set differently, but my "Blend if" slider has a different look to it. It only has 2 numbers for the two sliders. In your example there are 4 numbers with the "/" separating them. Is there something I need to change. I'm using CS2, has this just been changed?
As always, thanks!