resizing down, adjusting levels best practice

[NickGross]

G'day guys,

I have 3 fairly newbie questions about photoshop that I definately should know by now, if anyone can help out I would be very grateful.

1. I want to resize down an image that is at 300dpi from about 134mm to 120mm: is it better to resample so I end up with an image that is still 300dpi, or is it better to uncheck resample, input the required size and end up with an odd higher dpi image at something like 332 My concern is that if I don't resample it in photoshop, it will be resmapled down at some point in the chain from indesign > pdf > press and perhaps it won't be done as smartly as photoshop. I hope this makes sense.

2. My research has led me to believe that it is far better to resize in pshop then indesign because indesign simply makes the pixels bigger, is this correct?

3. I was chatting with a bloke from my printer who was coaching me on level adjustments in photoshop. He said, in grayscale at least, it was better to make the output levels something like 10/245 instead of 0/250 so that you don't ever have a complete black or a complete white, so it's better for halftoning. This seems fair enough, but if I want to adjust the contrast and brightness of a picture, should I restrict myself to levels only? I have been using the brightness/contrast dialogs first, because I can control it better, and then I am going into levels to change the output levels to preserve the tone, perhaps I am wasting my time? I don't want to enter the world of curves yet, seems a little bit advanced atm. I guess my question is: what is a good way to correct flat photos in photoshop? Am I wasting my time with this 10/245 thing?

thanks for any help, greatly appreciated, have been trawling on google for far too long to try and find these answers and I have a lot of photos to scan, I want to get them right,
cheers

Nick

 

[jmgalvin]

Don't resample. The more pixels the better. If you want to resize up a bit, those extra pixels allow it. IF it's 300 dpi it cannot be upped a bit without l;oss of quality.

The standard press pdf export (or acrobat distiller created) pdf will do a superb job of reducing to 300 dpi. It's becoming the standard of the whole printing industry and you see the results every day in magazines, etc.

Resizing down in Indesign works the same as resizing down in PSD without resampling. The apparanet dpi increases. If this is going to be placed in Indesign, you don't have to make it smaller in PSD. It's just as easy and foolproof to resize down in indesign.

I have to change color photos to grayscale all the time for newspapers. After I change to grayscale I work teh brightness-contrast a bit. I hardly ever touch levels and have never had a problem. I do play the curves sometimes - usually to bring out facial features it a face tends to blend with the background. Just make a copy of the pic and play with the curves if you like. You can alwyas go back to the original.

Using OSX 10.3.9 on a G4

 

[rickwells]

Try the SHADOW/HIGHLIGHT controls. Go to - IMAGE>ADJUSTMENTS and choose Shadow/Highlight. The default setting is pretty good, but play around with the controls ( on duplicated image ). Pushing up the "Midtone Contrast" slider works wonders ( for me ) on greyscale pictures.

 

[NickGross]

Thanks Rick and Jm that's really helpful,

So to clarify, it isn't a problem to have a complete white (paper) value and a complete black value in one colour work? My printer's been telling me that it starts to 'fill-in' if it gets too much black and that you can get a 'jagged edge' (where the dots finish) if you have complete white ... Do you guys set the output values after you've finished monkeying with the brightness/contrast to prevent this? Is it a problem?

I like 'play the curves' as a phrase, it seems to capure well the feeling that you're gambling just a little bit
cheers

--N

 

[jmgalvin]

Again, I've never had a problem with any photo. I just try to make them look as natural as possible and don't worry about much else. I really don't bother checking what colors are in the pic.

The original question mentioned grayscale. If you're working in color, make sure to set the mode to cmyk, not rgb, for print.





Using OSX 10.3.9 on a G4

 

[rickwells]

You need to allow for "dot Gain" when assesing how your finished print will look. This issue takes some getting to grips with and is not something that can be explained thoroughly in a forum answer. Do a search in Google. Here's one link which will help explain what your printer is saying;-

http://www.umax.co.uk/support/binuscan/technotes/nbi01.htm

I would also suggest that you spend some time trying to get the very best from your scanner. What is the spec and what software is used ?

I never use Brightness/Contrast controls unless I want to quickly flatten an image. It's very destructive. Levels, beter still, curves are much more controllable.
Again, do a search for tutorials - there are plenty about.

No, there's no reason why you shouldn't have 0% in the highlights and 100% in the shadows.

My printer has just installed a new press which can hold a 1%^ highlight dot and maintian an open dot very close to 100%.

Like jmgalvin I generally don't have any problems with photos but we probably take for granted our experise which has built up over the years.