Enlarging a file to 100mb??

I need to enlarge my tiff files from around 50mb to 100mb for printing. How can I accomplish this and will it affect my image quality?

Thanks everyone!!

I am going to back up a step on your question, just to make sure everyone is on the same page here. Do you want to increase the file size or the number of pixels contained within the file?

Usually, when you want to increase the size of a file for printing, you increase the number of pixels and let the file size fall where it may.

Under ordinary circumstances, such as with a "standard" home printer, which includes the high end machines such as the Epson 9800 series. Let's suppose you start with a file that is 4,000 x 5,000 pixels. With 8 bit color, your file size will be approximately 4x5x3 = 60 mb. (The three is 1 byte per color, three colors red, blue and green). The most usual file enlargement is because you want to print it bigger, such as a file than needs to be sized at 6,000 x7,500 pixels, which would be 135 mb. In that case, go to Photoshop (any recent version) and do the following:

(If you are working with 16 bit color, the above file sizes would be 120 mb and 270 mb, more or less)

Go to the image drop down

Select image size

A box will pop up.

If your starting file is 4,000 x 5,000 pixels, you'll see the width and height containing these numbers. Assuming that you intend to keep these proportions, make sure the box at the lower left marked "constrain proportions" is checked.

First, in that box, there is a box marked resolution. Enter the number of pixels per in you want to print at. As a basic rule of thumb, I use 360 film film capture and 240 for digital. Why? Because for me, this works. If you are using an outside printing company, they can tell you what number to put there. (There will be a note below with a qualification for this)

Now go back up to the two top boxes. Fill in either 6,000 or 7,500 in one of the two boxes, as appropriate. The other one will change automatically.

At the bottom will allow you so select an interpolation method. Make sure to select bicubic. Newer versions also add a comment as to which one to select (this on for enlarging, this one for shrinking).

Hit okay.

Wait a little bit.

Save the file UNDER A DIFFERENT FILE NAME!!!!!


Here is the qualification I mentioned above. Sometimes, if you talk to an external printing service, you may say I want this printed at 20x30. What size file do you need? They may tell you "give us a file that is 6000x7500 pixels". In this case, the number you put in the resolution box is irrelevant. Assuming that you are dealing with a professional service, they'll take care of making sure the right number is there. Just to be safe, because there are a fair number of idiots out there running machines, it won't hurt to stick 300 in there.

Some people recommend doing an upsize in steps no more than 10% at a time. For example, starting with a file that is 4000 pixels on a side, go to 4400, then 4840 (okay make it 4800), etc. The current start of the art seems to indicate that this really isn't necessary anymore, but it was in the stone ages of digital photography, a far and distant 10 years ago.

If you are working with the guy Jerry recommended, just ask ask him about the files sizes needed, including the number of pixels. My best guess is that the 100 mb size was mentioned since the number of megapixels that would contain should cover most reasonable printing jobs.

If changing the number of pixels in the file is not what you are after, I haven't a clue as to what you need. If you are currently working in 8 bit, I see no real advantage to converting to 16 bit for the purposes of saving the file, although I'd recommending working in 16 bit mode for image editing.

I am working with John Smith, he said that he prefers 300 dpi, which my files are already in, it's in ppi though...which I imagine is the same. He also said he likes the tiff files to be 100mb, but that he has an "upsizer" or something on his printer that will fix it for me if I can't do it on my home computer. I was just curious how I could do it at home. I would think that changing my file size, pixel amount, would mess my image up.

So yes...I think I need to up my pixel count. Is it as easy as that or are there things I'll have to do to the image after the resize? Should I let him do it in the lab with his stuff?

I'm sorry about all these questions as of late, I'm still wet behind the ears though.

Thanks for all your help!!

There's no way around it - if there are not enough pixels in your images you will need to add them. You can do this in Photoshop or other imaging software, or in some cases the printer driver can do it for you.
One reason to do it yourself is that you will ideally want to sharpen the file at its output size.

Guy

How big are you planning to print? The other thing is that it probably doesn't make much sense to provide a file that big if you are looking for 4x6's. From earlier threads, I think you are planning to go much larger than that. Also, does he want the file as 8 bit or 16 bit?

Don't worry about asking questions - we all have to start somewhere!

One additional comment on what Dan said about enlarging a little at a time. According to a couple of sources I've seen (include Luminous Landscape), this isn't necessary anymore. The algorithms used in Photoshop to enlarge an image can be done in one step, with results just as good as multi-pass. The multi-pass elargement doing 10% at a time should not be required anymore, but was in some older versions of the software.

Of course, you'll still likely want to do some light sharpening one the file is upsized.

(And keep in mind that all of this is in order to acheive the best possible print quality, and not have anything funky result, like bad colors or soft images. If I'm making a print just to give to a friend who I know isn't picky, I'll just let the printer driver, or a program like QImage, do all the upsizing and sharpening for me. I lose some control, but in some cases I don't care.)

Dave, thanks for the clarification on the upsizing.

good info, thanks everyone.

I'm just wanting some 8 x 10 prints for now. I don't think that my Rebel XT would put out a good 16 x 20 would it?

And I dunno if he wants it in 8 bit or 16 bit, I don't remember him specifying.

Thanks!!

The XT has a native resolution of 3456x2304. This means that with no interpolation you can print to about 7.5x11.5 at 300ppi. For an 8x10 you will need to crop a little and interpolate a little but that should not cause any significant loss of image quality.

At 8-bit, 300ppi, an 8x10 file will be about 22MB. At 16-bit it will be twice that. Either way, there is absolutely no need for a 100MB file for that size.

Guy

Thanks Guy....do you think an XT can put out a quality 16x20??

Kyle, I have made prints to 20x30 with the 20D/30D and XT. Some were smashing. Others that depended on lots of fine small detail "fell apart" quality wise before I got to that size, but printed very well at 13x19. In my experience ultimate print size must depend somewhat on the subject. IMO, those simple compositions with a few elements and broad expanses of color can be made larger than the images of fine detail.

My experience also has been limited to what the native interpolation (adding pixels) in Photoshop CS and CS2 is capable of, however. There are enlarging programs out there that are supposed to do a better job.

Lens quality is another factor. Poorer lenses deliver native IQ that makes big enlargements harder than those captured with top lenses. Iso and noise also factor in. The lower the iso and noise, the better your chances of making large prints that look good enough to hang/sell.

These are all very general statements, and your results may vary.

But since you're pursuing working with a specific, very professional and particular photo print service, I suggest getting some prints done in various sizes to see whether you and he are satisfied with it, and since he has a ton of expertise, you may simply give him your file and see how large he can make it before it goes south. While it will cost a bit of money, actually getting prints made and comparing them is the only way to settle the issue in your mind.

Thanks Guy....do you think an XT can put out a quality 16x20??

That depends as much on the image as it does on the camera. With the right image you could get very nice 16x20s. It will not be "tack sharp" with your nose up to it, but it will look very good at normal viewing distance.

Guy

Thanks!!

One more quick question. Why does the XT take a photo at 7.5x11.5 and not some standard photo size?

Also, are there more large standard print sizes then 8x10 and 16x20? I just don't see frames for much anything else. Do you have to special order frames for other sizes??

Thanks everyone, you have been a ton of help!

Kyle, most small-format SLRs and DSLRs use a 2:3 image ratio, which fits some standard sizes (e.g. 12x18, 16x24 etc.) though these are unfortunately less common with photo labs and standard frame sizes.
I believe the history of it dates back to the first 35mm film when a decision was made to make the aspect ratio closer to the "Golden Mean", though I'm not certain that was the case.

Guy

Kyle, most top print labs offer quite a bit variety of print sizes in non "traditional" ratios. I do most of my frame ordering through Dick Blick art supply, which is online. They offer tons of frame options. You also can order frames online through some framing outlets cut to specific sizes.