PDV-3e desktop viewing stand review
PDV-3e desktop viewing stand – review
A D50 desktop viewer for print proofing and evaluation
Our ‘home made’ one finally started to show its age, so we decided to look at getting a good reliable commercial model.
In this review, Keith has a look at the PDV-3e/D kindly supplied by the UK office of GTI.
The review also contains information about print viewing in general that should be of use, even if a full size stand is beyond your means.
GTI supply a range of print (and transparency) viewing options that range from basic desktop stands to complex viewing stands for use in printers and design studios.
The stand I’m looking at here is one of their ‘PDV’ Portable Desktop Viewers, which come in a variety of sizes and options. [PDV info from manufacturer]
|PDV-1e||11.7″ x 16.3 ”
(30 cm x 41 cm)
|13″ x 19.3″
(33 cm x 49 cm)
|PDV-2eTR, PDV-2eTR/D||13″ x 19.3″
(33 cm x 49 cm)
|8″ x 10 ”
(20 cm x 25 cm)
|16.5″ x 25.3 ”
(42 cm x 64 cm)
|PDV-3eTR, PDV-3eTR/D||16.5″ x 25.3 ”
(42 cm x 64 cm)
|8″ x 12 ”
(20 cm x 30 cm)
|23.5″ x 25.3 ”
(60 cm x 64 cm)
I picked the PDV-3e, since we often produce prints at A2 size (no transparencies though)
The next question to decide is whether you need the dimmable version.
Fluorescent tubes like the ones used here, are not easy to adjust in brightness, and require relatively complex circuitry to give consistent results.
The main reason for dimming the light levels is to match the brightness of your monitor when checking soft proofing. I’ll show some examples of this later, but once you get the hang of using it, it can help considerably in producing consistently better prints.
The units are dimmed with a simple rotary control.
Just in case you were wondering, the units are not orange in colour, I’ve just white balanced the pictures to the light inside the stand. That orange comes from a normal domestic 100W lightbulb in the room. Our eyes adapt very quickly to different lighting colour temperatures – cameras not so easily.
I’ve also gone for the (detachable) side panels, which are optional, but help shield the viewing area from extraneous light.
The devices themselves are mostly built of aluminium and hinged so they can fold up for transportation or storage. One useful feature was the extra long power lead that came with mine.
If you look at the top of the viewing area, you can see a reflective strip.
This has a print holding mechanism, where small rollers in a slot hold prints in place at the top of the viewing area.
Unfortunately this often leaves marks along the edges of prints, particularly papers with more delicate surfaces.
There is a slight gap between this strip and the back surface, which I found would grip prints if they were slid up into it.
The tubes are in the top of the unit, so you should be careful to look slightly downwards on prints, so as not to directly have the tubes in view.
Note – We’re told that a minor design change has been made in this respect, and additional shielding has been added in front of the bulbs. GTI are sending us the update. This will help where, like us, you have the unit on a desk at the same height as your work area. When I turn to look at prints I do need to ‘sit up’ a bit to avoid any direct sight of the bulbs. The picture below shows the sheild in place (it is easy to fit and removable)
The devices are designed to match to the D50 ISO 3664:2000 viewing standard. This covers factors such as the spectral quality of the light, the evenness and levels of illumination. The unit should be switched on at least 15 minutes for very critical work, since colour temperature can be off by a bit as the tubes warm up.
There is a PDF from GTI which has more details on what the ISO standard stipulates.
Those two fluorescent tubes (Graphiclite 100) at the top are what govern the quality of the light and how well it matches the D50 standard.
It’s important to note that D50 is a ‘made up’ theoretical light source – there is no such thing as a ‘real’ D50 lamp.
The spectral plot at the right (from GTI), represents the output spectrum of the lamps, compared to the D50 standard ( ‘A’ black line).
You’ll notice that there are a few sharp spikes in the output, but there is a fairly broad spectrum, with no obvious missing bits.
Comparing the spectrum to another ‘5000K’ fluorescent tube (lower graph) shows the relative spikiness of the spectrum.
You may see the CRI (Colour Rendition Index) of tubes mentioned as a measure of how good they are. This can be misleading since a tube could have a slightly higher CRI number, but possibly be worse for proofing and print evaluation.
CRI is a measure of the degree of colour shift objects undergo when illuminated by a light source, as compared with the colour of those same objects when illuminated by a reference illuminant of comparable (within 100K) colour temperature.
Based on a scale of 0 to 100, a rating of 90 or higher is required for critical colour evaluation applications. [GTI technote on CRI – PDF]
If you were planning to make your own viewing stand – I’d suggest that spending the extra on some good quality lamps is a very good idea. Our old one just smelt of hot wood once too often and it would take some explaining if it burnt the place down :-)
GTI sell the lamps directly and through distributors. If you use them for your own devices, then do remember that the quality of a viewing system relies on all its parts. The lamps are actually just over 5000K so that when combined in the viewing system, the net illumination is very close to 5000K.
OK, it’s just a box with lights in it (as one visitor to the office noted), but there are a number of considerations in getting the best out of kit like this…
First of all, if it’s on a desktop, you don’t want that colour reflecting onto your prints.
The picture below shows a sheet of neutral grey photo backdrop cut to size, to cover the top of the desk the PDV-3e/D sits on.
I don’t work in a grey room and don’t wear grey clothes. Some more colour critical applications may demand this, although I understand that setting up a completely grey colourless design studio is a sure-fire way to increase staff sickness rates.
Consider other room lighting as well. The picture below, shows an i1 iSis printer profiling target that I was recently testing for OBA (optical brightener) levels.
The main room light (tungsten) is on here and you can see the noticeably warmer area in the lower half of the viewing area.
This is easily visible in a photograph, but once pointed out, is quite noticeable to the eye.
Dim lighting is what’s needed for working, but is a right pain when moving cables or finding something you’ve dropped…
In my office, the viewing stand is 5-6 feet away from my main monitor and at right angles to it. This means that I have to turn my head when looking from screen to print.
My monitor is set to a colour temperature of 6500K, whilst the viewing stand is at about 5000K (for D50).
Colour temperature? A quick reminder [WP article].
|Temperature||Common name||Overall colour tint|
|7500K (D75)||North Sky Daylight||Moderate to Deep Blue|
|6500K (D65)||Average Daylight||Moderate Blue|
|5000K (D50)||Equal Energy Daylight||White|
|4100K||Various fluorescent sources||Greenish|
|3000K||Warm fluorescent sources||Orangish|
|2865K||Illuminant A||Yellowish Red|
In the examples below I’ve deliberately put the stand next to my 15″ Mac PowerBook – they are on a brown wooden table too, but we’ll let that go for this test (but look carefully at the following images and see if you can notice its effect).
I’ve dimmed the viewer to match the brightness of my laptop screen showing a white display (an empty folder opened up is a quick way of getting this).
There is a plain white box of print paper in the viewer.
Notice how the laptop looks neutral and the paper rather warm?
One version of the image is set for ~5000K and the other ~6500K (original photo was shot in RAW format and then converted twice with different white balance settings).
It looks quite noticeable here, but in the fraction of a second it takes to move from one to another (in the set-up in my office) your eye will fully compensate for the shift in colour temperature.
You may see people suggest setting your monitor to 5000K for evaluation like this, but unless you are doing very specific print proofing, most people find a monitor set to 5000K far too dark and drab looking.
Modern LCD displays also work a lot more efficiently when set for the higher 6500K.
Do remember too that D50 is an exact specified ‘Standard illuminant’, which is what the viewer aims to provide. There are actually a range of colours (ranging from greenish to magenta tinges) that all have a corrected colour temperature (CCT) of 5000K. A D50 source will have a CCT of 5000K, but a lamp with a CCT of 5000K will not automatically be close to D50.
In the image below, I’ve set the viewer to the same brightness as the laptop and white balanced the picture here to the white of the paper.
The more pronounced blues in the screen come from the higher display colour temperature and in this side by side comparison, it’s quite easy to see.
Looking at one image at a time makes this much less noticeable, and the match is much better.
I’m using Photoshop for my image editing. You can address these differences to some extent by setting up softproofing and looking at the image with ‘Paper White’ selected.
There are a number of other things you should be aware of when first trying out this stuff…
Look at the screen below. There are white interface elements visible – these will often show parts in ‘pure white’ i.e. whatever your display is calibrated too. If you are simulating ‘paper white’ then you should hide these, since they will cause the whites of your image to not look fully white.
The accuracy of the image displayed is dependent on the capabilities of your monitor. I’ve just calibrated the one here with the Spyder 3 Elite you can see sitting next to the laptop.
The gamut (range of colours) that the screen can display may be somewhat less for some colours, than your printer can manage.
In this instance, the laptop display has difficulties with some of the strong leaf colours. I’d always try to avoid any serious editing on a laptop using its own display.
If you are soft proofing, then the accuracy also depends on the quality of your printer profiles.
Using a proper viewer to evaluate aspects of a profile is in fact one of the few times where I might consider editing or rebuilding a profile, so as to improve soft proofing accuracy.
I had heard that it can be difficult to match lighting levels between a white bit of screen and white paper. I took the approach that the spot meter in my Canon 1Ds3 is pretty good, so just pointed it at the screen and got a reading. I then pointed it at the middle of a sheet of paper and adjusted the viewer to get the same reading – just a few seconds work.
The PDV-3e print viewer is superficially a simple device, this belies a lot of the design work that has gone into making sure it meets standards such as the ISO 3664:2000 viewing specifications.
I often get asked for suggestions about learning more about the nuts and bolts of Colour Management.
My usual suggestion is Bruce Fraser's Real World Colour Management. My own copy is well thumbed. It's my first port of call if I'm asked a question and I feel I don't quite understand an issue well enough to be absolutely sure of an answer.
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See some other books Keith has on the shelf, on our Books Page
I’d suggest that unless you are producing specific accurate proofs and working to exacting standards, the actual details of ISO 3664:2000 are probably not that important to you (it’s more aimed at manufacturers of viewing devices than end users).
This particular review is written from the point of a fine art print maker wanting to adopt a more consistent and efficient workflow. If you are regularly producing proofs for clients, I’m wondering why you don’t already have something like the PDV-3e?
At Northlight we also provide basic colour management training and advice to a lot of companies. Inconsistent colour reproduction is a problem that recurs again and again. In a business, colour management contributes to the bottom line by helping you get it right first time more often.
The standard (non-dimmable) version allows you to critically examine prints for imperfections and overall print quality.
It works very well in this respect, although do take note of the need to ensure that the surrounding environment is appropriate for critical print viewing. Having an open window behind the stand, or a desk lamp lighting up half of the viewing area just wastes much of the effort and expense you’ve gone to.
The print holding mechanism at the top of the viewer still has a tendency to leave marks on more delicate papers. The examples in this review were photographed before we found that there was an alternative way of holding papers under the bar. Since the unit is built from aluminium, you can’t use magnets to hold prints in place.
I’m going to assume that you are pretty serious about your print quality if you are going to the expense of purchasing a viewer, as such, we decided that the extra for the dimming option would be well worth while.
Soft proofing takes some getting used to. Many people are quite horrified to see the effects of turning it on in Photoshop. What looks a great image is all of a sudden washed out and dull.
You may want to try different options of ‘paper white’ and ‘simulate black ink’ to get an idea of what different aspects of your print will look like.
How is the print viewer part of ‘Soft Proofing’?
Let’s consider a print like this sunset one at Rutland Water in the UK.
The image here is the actual print file, converted to sRGB and resized to 400 pixels wide for web use.
Compare it to the photograph of the print in the viewer above. It’s the same file that is being displayed on the laptop.
I’ve produced the image from a Canon 1Ds Mk3 RAW file and converted it (with DxO Optics Pro) to a 16 bit RGB file in the large ProPhoto colour space.
One of my reasons for picking this larger space is that this image has a large dynamic range and I want to avoid clipping channels where possible. From a colour gamut point of view, the image fits into the Adobe98 colour space, so there may not be much to be gained. I’m not wanting to get into colour space arguments here, since different ones have different benefits and disadvantages (and fan clubs)
After some editing, I’ve looked at it in soft proof mode in Photoshop and made a few more tweaks.
I’ve printed it on to a lustre finish paper (Pinnacle oyster/lustre) using an ICC printer profile built in-house.
It so happens that I’m quite familiar with this particular paper and have a fairly good feel for what a print will look like compared to a screen view.
However, I’m of the opinion that I don’t print enough with this paper to have much more than a ‘fairly good feel’ for it. By comparing the actual print with the Photoshop Soft Proof, I can see how accurate the soft proofing is – it also helps tell me if there is something wrong with my profile.
It so happened that the first image I tested the soft proofing with was the Datacolor Test Image we have on this site.
This is a ‘known good image’ and with a good profile, should look very similar in Soft Proof mode on screen to the printed version. I spent some time working out what differences there were between different proofing modes and how the physical print looked in the viewer. It’s this experience that helps make soft proofing genuinely useful as part of the print process.
The more confident I am that the soft proof represents the real print, the more I can rely on it before making my first print version of an image. If I couldn’t trust that the soft proof looked like the print, then it wouldn’t help me that much.
We produce high quality prints as part of our business – going for a well characterised device like the PDV-3e gives us greater confidence in the quality of our final prints. The dimmable option also makes matching prints to what we see on the screen a whole lot easier and more consistent.
A more consistent print workflow raises our quality levels, reduces time spent on hit and miss adjustments and lessens waste in our print making.
The PDV-3e/D dimmable print viewing stand allows for critical evaluation of print quality and when matched to the brightness of a screen, can improve the effectiveness of soft proofing.
The PDV-3e/D is part of a range of D50 viewing solutions made by GTI. These are sold via numerous distributors worldwide.
Current list prices (UK excl. VAT).
|PDV-3e Folding Desk Viewer 42 x 64cm||£385.00|
|PDV-3e/D Folding Desk Viewer with Dimming||£610.00|
|SW/PDV-3 Side Walls||£ 60.00|
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