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Converting TIF to JPEG while preserving 300dpi resolution
LABachlr




msg:858546
 10:48 am on Apr 5, 2003 (gmt 0)

How can I convert a TIF image, that I created by scanning in a photo, to a JPEG image while keeping the resolution at 300dpi? I scanned it in at 300dpi.

I have Photoshop 7 and have tried all that I know. No matter what I do, it converts it to 72dpi.

Any ideas?

 

Duckula




msg:858547
 11:19 am on Apr 5, 2003 (gmt 0)

The jpeg conversion is taking away all the quality anyway. Why not just resizing the resulting 72dpi?

Longhaired Genius




msg:858548
 5:44 pm on Apr 5, 2003 (gmt 0)

Everything depends on what you want to do with the image. You haven't really given enough information for people to give you meaningful advice.

LABachlr




msg:858549
 5:52 pm on Apr 5, 2003 (gmt 0)

I am creating an image in photoshop that a printer is going to use to make a postcard to advertise my website. He needs it in 300dpi resolution in order for it to print correctly. I have already created the vector image, but need to add photos to the image. He said that everything needs to be in 300dpi resolution, including the photos that I add to the image.

I already have one photo that is in jpeg format that is 300dpi, but I did not create that. I scanned in a photo at 300dpi as a tif file, and would like to convert it to jpeg while preserving its 300dpi resolution.

Longhaired Genius




msg:858550
 6:15 pm on Apr 5, 2003 (gmt 0)

If you are doing the design yourself and will be handing the resulting file to the printer to print it will probably be okay to save everything in photoshop format. But ask him, to make sure.

If the printer's designer is going to do some of the final composition, he will be able to use your tiff and your jpeg.

Either way it seems to me you don't need to convert your tiff to jpeg.

But I'm not a designer (or a printer), so there may be something I've missed.

LABachlr




msg:858551
 6:48 pm on Apr 5, 2003 (gmt 0)

My whole reason for converting to jpeg is so I can add a drop shadow to it in fireworks before I add it to the vector image. However, I was just told that you can do everything to a TIF file that you can do to a jpeg file. But for some reason, I can not add a new layer to the TIF image to add the drop shadow, and it is in rgb color. All of the selections under the Layer menu are grayed out, and when I put my cursor over the "new layer" button, it gives me a circle with a line through it.

Longhaired Genius




msg:858552
 7:15 pm on Apr 5, 2003 (gmt 0)

Hmm... I'm a bit out of my depth now.

Plenty of Photoshop experts use these forums but it looks like they're not on line. You might have to wait till they get into work on Monday morning when you can bump this thread back up to the top of New Posts.

Sorry I can't be more help.

matkat




msg:858553
 7:42 pm on Apr 5, 2003 (gmt 0)

Your tif should be in CMYK for printing. Save it in Photoshop as CMYK and then you can open it in Fireworks to add the drop shadow.

LABachlr




msg:858554
 7:45 pm on Apr 5, 2003 (gmt 0)

Actually, all I had to do was change it to 8 bits/channel. It was in 16 bits per channel, and I couldn't do anything with it..couldn't add a new layer, couldn't open it up in fireworks...nothing. Now I can do whatever I want with it. And btw, it was and still is in RGB color.

tedster




msg:858555
 8:56 pm on Apr 5, 2003 (gmt 0)

The final print piece will come out in CMYK, which has a much more limited color range, or "gamut", than RGB. So I'd advise doing the conversion to CMYK yourself to avoid being surprised by any unfortunate color shifts.

LABachlr




msg:858556
 10:18 pm on Apr 5, 2003 (gmt 0)

Thanks for the tip. Actually, the piece I am working on is black and white. I called the guy at the print shop, and he said just to switch it to grayscale. And he said that even if I don't, that he will end up having to anyway. So using the same reasoning as your example, I should switch it to grayscale just to be sure I am going to get what I see now.

BTW, when I try switching it to grayscale, it says, "Changing modes will affect layer compositing. Flatten image before mode change?" I assume this is OK to do in this situation. I obviously won't do it until I am completely finished.

tedster




msg:858557
 10:30 pm on Apr 5, 2003 (gmt 0)

Right, it's fine to flatten the layers as a last step.

Sometimes grayscale conversion doesn't give a very good looking image. Another approach you might try after flattening the layers is to go to L*a*b color space, go into Channels and then select the L channel (Lightness). Select All, Copy and then return to RGB and paste the copied channel onto your image and flatten again.

The "L" channel in L*a*b color space often preserves subtle shades of gray detail and a better black to white distribution than a straightforward grayscale conversion (or a "Desaturate, which also removes all color.)

LABachlr




msg:858558
 1:02 am on Apr 6, 2003 (gmt 0)

You really know your stuff. Thanks. I'll look into it when I finish.

benihana




msg:858559
 1:05 pm on Apr 6, 2003 (gmt 0)

reason for converting to jpeg is so I can add a drop shadow to it in fireworks

coud you not do this in photoshop instead?

LABachlr




msg:858560
 2:14 am on Apr 7, 2003 (gmt 0)

Yes, I could have. But I wanted the drop shadow to match the drop shadow that I gave to the other pictures in Fireworks exactly, and I did not feel like noting all of the settings for the drop shadow in Fireworks and applying them to that function in Photoshop.

Jon_King




msg:858561
 2:21 am on Apr 7, 2003 (gmt 0)

This is easily done in Photoshop. If you are encountering problems with jpegs you are likely using the "save for web" option for creating your jpeg.
Use "save as" instead and choose jpg from the file type drop down. This will allow for CMYK 300 dpi (or any dpi) jpg files.

LABachlr




msg:858562
 3:40 am on Apr 7, 2003 (gmt 0)

You are asolutely right! I am so used to using "save for the web" that I didn't even think of that. Good to know for next time. Thanks!

Bendy




msg:858563
 12:24 pm on Apr 7, 2003 (gmt 0)

When saving a .jpg for print from Photoshop ensure the you have selected BASELINE ("STANDARD") and keep the IMAGE OPTIONS optimisation as high as possible if you intend doing more work to the image . . . if the image is finsihed being edited you can probably optimise to a quality of about 7 without too much degradation of the image. I know this because I prepare images for magazines on a regular basis.

LABachlr




msg:858564
 4:42 pm on Apr 7, 2003 (gmt 0)

OK. Thanks for the tip.

dodo12




msg:858565
 6:43 pm on Apr 21, 2003 (gmt 0)

Mmm!

loverty




msg:858566
 12:50 am on Apr 22, 2003 (gmt 0)

you can try to use Fireworks

piskie




msg:858567
 1:10 am on Apr 22, 2003 (gmt 0)

I think you should try taking your tif straight into Fireworks.

You can then do all you want including your drop shadow and save/export as whatever takes your fancy in whatever DPI you wish.

Including a step using another application is an unnnecessary complication.

cayleyv




msg:858568
 5:51 am on Apr 23, 2003 (gmt 0)

I second Jon_King. Use save as in photoshop and you can keep the DPI at whatever resolution you want. Save for web assumes you are totally unaware of what you are doing - PS tries to do everything for you.

netcommr




msg:858569
 3:24 am on Apr 29, 2003 (gmt 0)


If all you need to do is set the DPI, I would suggest IrfanView [irfanview.com]. Just open your image and select Image, Information. This has a place to set DPI. You can also do a batch conversion to set the DPI in multiple images at once.

ImageWorks




msg:858570
 9:59 pm on May 8, 2003 (gmt 0)

Just a heads up when preparing any content for print - make sure you've taken the file as far toward finalization as possible, otherwise expect printer "touchup" costs.

Additionally, JPEGS sometimes have issues with particular RIP processes, so TIFFS are the preferred filetype for professional image manipulation.

Lastly, "Changing modes will affect layer compositing. Flatten image before mode change?" is a safety mechanism that Photoshop has regarding color shifting. It's just a warning that color *may* be altered. It's often alright to work with the file even after the mode switch WITHOUT flattening the file. Just keep in mind that a shift has occurred and be careful to watch for color change.

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