Jessops prints: some too light

After a holiday trip I gave my digital pictures (on CD) to my local Jessops branch (287 pics 7x5). Most of the pictures were really good (although a bit darker than I would have expected but that could well be my monitor setting). However, 25 of them didn't turn out well, most of these being 'overexposed' i.e. details in light areas were gone. These light pictures seemed nothing different from the o.k. ones on the screen (neither gave looking at the histograms any clues).
On the weekend I went back to them to find out what's happening. I was told that they don't do anything to the pictures once they are sent from the 'editing station' (or whatever they call the fancy PC where you put your media in and select/edit your pictures). So that begs the question what the machine is doing to them. It's rather odd, since I had the same motive shot twice, once in landscape once in portrait. On the screen they look the same, the histograms look very similar, but one came out too light and the other one o.k.
Can anyone shine light on this one or has had the same experience? What print services do you use?

P.S.: After looking at the pictures on CD and the prints I got a refund on the prints (on their own suggestion!) which is very nice, but it would have been even nicer to know what's happening to avoid it next time round...

Prieni,

The first thing is to calibrate your monitor. Download Wyziwyg from www.praxisoft.com. It's free and takes about 10 minutes to profile your monitor. That might make a difference.

I've used Jessops before, via the Internet. The in-shop service locally was dire and I tried to use them a few times (once I received some gift tokens from head office). Just gave up and use the Internet.

Here are some others to try:
www.photobox.co.uk - they don't tweak the photos. I haven't tried them yet, but will next week
Boots. Again, heard good reports, but might depend on the staff at the branch.

(For my personal 6x4 shots I now use a HiTi Photoshuttle dye sublimation printer, which works out at 35p per print. www.hitishop.co.uk . Exceedingly useful and covers 90% of my print needs)

(I am sure others will be able to comment too)
Matt

Thanks Matt.

I downloaded Wyziwyg and went through the calibration of my display. However, I ended up with a quite yellowish picture (gray being very brownish). Anyway, that might adjust for the majority of the prints I got from Jessops (the o.k. ones) being a tad darker than on the monitor. But it doesn't explain why some pics are coming out too bright.
You say that photobox don't tweak the photos, the Jessop man said they don't do that either (and again, for the o.k. ones that seems to be true). Seems that the machine is doing something to some photos. To make matters worse it's doing that in an unpredictable fashion
Maybe I try Photobox next time round and there's always the last resort of printing them out myself (although that comes out much more expensive, at least for small prints).
That brings me to another question: Where can I get A3 size prints? Would I need to increase resolution or would 3008 x 2008 be o.k.?

Prieni

Prieni,

Getting the gamma right is one thing - squint at the monitor while adjusting. I find the best approach is to work out the upper and lower limits that you can see a change for, then set the mid-point. You also have to get the right phosphor (or use Generic LCD if using LCD TFT). It's a "best-shot" approach. The best way is to buy one of those "spiders" that actually measure the colours on screen. But that'll set you back a bit

Sounds strange about the light images. From what I recall, most of the printing equipment has the choice for "auto adjust" and "leave alone". Sometimes you find that someone's changed the option by mistake. What I can say, though, is that the internet printing has been very consistent with Jessops.

You'll find that www.photobox.co.uk print out to A3, and even A2 What they say in their "Quality Advice" section is that A3 requires at least 2000 pixels on the longest side, and A2 requires at least 2400 pixels. So you should be just fine with 3008x2008.

Best thing is to send a couple for trial and judge them on that
(Something I must get round to doing for large format!)

Matt