[Scribus] quality images for press (digital camera? cheap/free online stock s? scan?)
Wed May 4 21:59:19 CEST 2005
I've been a professional photographer for almost twenty five years, and
have been working 100% digitally for the last five years.
The sort answer to your question is that it all depends on the size and
quality of output you are expecting.
Some years ago (mid 80's) I remember the UK pro photo mags getting very
excited because Hasselblads could at last be fitted with a digital back
(made by Leaf) which had a resolution of about 4M pixels. (The
Hasselblad, for those who don't know is a favourite pro photographers
camera. It's totally modular and comprises a body, lens, viewfinder,
winder and film or digital back. All these parts are interchangeable so
that an ideal camera can easily be built in a couple of minutes to suit
the job in hand.) The magazine publishers were excited because this Leaf
back was capable of image quality which wqas virtually indistinguishable
from film when used for a glossy magazine cover.
I mention this for several reasons, and I'd like to explain the
importance of each reason in turn. This may take some time, but I hope
it's worth it.
First, the size of the output for comparison was only A4. With an image
sensor of 2048 x 2048 pixels, the pixel density on a page about 8" wide
could be as high as 256 pixels per inch. (PPI)
This PPI figure equates well to the "lines per inch" normally quoted by
litho printers, since each recorded pixel must be represented by a
pattern of many dots by either a litho or standard desktop (ie inkjet)
printer. Few printers will work to much higher than 200 LPI for normal
use, even on high quality glossy media, so this resolution is certainly
plenty for this purpose.
Second, the relationship of printed size and viewing distance must be
taken into account. The same image printed at A2 (ie, twice as large in
both directions) would have an effective resolution of just 128 PPI. A
critical viewer would certainly be able to see flaws in the image if
they were to view it from the same distance as the A4 version. In
practice though, no-one will normally view an A2 image from eighteen
inches away and from a more sensible distance the flaws will be
invisible. The effect is similar to that for "depth of field", a much
misunderstood phenomenon for which the scale vs viewing distance part of
the equation is most often ignored by those who think they understand
Third, the pixel resolution is only one of the aspects of image quality
which will affect the result. At least as important are: dynamic range
of the sensor, recorded bit depth, compression method (if used) and of
course lens quality. Sadly, it's much harder to find information on any
of these factros than the pixel resolution. Once again, it's the result
of a market driven by a desire to sell to people who think they
understand what they are buying but in reality are over influenced by
advertisers looking for easy comparisons.
Lastly (for now at least!) the final quality you get from your printer
will be hugely influenced by all of the above, but also by the way you
prepare your images for printing and of course by the quality of the
printing device and its consumables. I have absolutely no knowledge of
your personal hardware setup, nor of whether you are using an external
printer (or their setup).
It may well be that your "local photography shop" (presumably you mean
they retail photographic equipment rather than photography) is giving
you excellent advice. I would certainly recommend a good lens, high
dynamic range sensor and uncompressed file save options over high pixel
resolution, unless you can afford all four of course! It's uncommonly
honest of a photo retailer to give this sort of advice and I'd suggest
you thank him for his honesty and reward him with your custom and loyalty.
Neil Lewis (photobod)
Gregory Pittman wrote:
> Tariq Rashid wrote:
>> my local photography shop (run by photography and optics enthusiasts)
>> that i don't need a digitial camera with more than 2MP - i don't believe
>> them! surely, the higher the pixels you can capture the more you can
>> and play with the image before it becomes unusable - cropping an already
>> small image will leave you with even less pixels obviously).
> I have had an Olympus 2020Z for several years now, and very pleased
> with its performance. Once you understand the settings on the camera,
> little if any image processing is necessary (if anything, maybe
> brightening up or improving contrast). After a trip, I take pictures
> straight out of the camera, run scribalbum.py, add captions and other
> comments and print, that's it. It has something like 2.3 megapixels,
> and I don't routinely save in the highest quality (which would be like
> tiff) -- usually save as jpeg. Since it still does everything I need,
> I have no plans to replace it. If I were buying new, I would get a
> 4-5 megapixel camera -- why? -- because I paid US$700 for my camera
> new, and now an equivalent Olympus 4-5 megapixel is about half that.
> It's hard to find a 2-3 megapixel camera, unless you're talking about
> one of these cheapie shirt-pocket cameras.
> My general recommendation to people over the years has been to try to
> pick a camera made by a "traditional" camera company, because the lens
> is important -- so go with Olympus, Canon, Nikon, etc., not Sony, not
> Kodak, not HP, and you don't have to go with a high-end SLR-like
> camera either. "Digital zoom" is a useless feature, but real lens
> zoom is great.
>> some have advised that i use an analogue camera and scan the developed
> This just adds another step of aggravation.
>> can anyone advise on any of this? is a 5MP camera enough? can anyone
>> recommended one that has a good end-to-end system (lens and
>> processor, not
>> just CCD).
>> one option which is a bit crafty is to use low resolution images and
>> blow them up and apply various artistic filters to hide the fact that
>> were originally of low resolution - even tracing it to a vector format.
> This may require a LOT of tweaking, and probably at best would give
> you an "OK" result. So, do you want people to say, "that's OK, I
> guess", or "Wow!"? You sound like you're wanting to make this quick,
> so make the camera do most of the work.
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