Review of the Dell 2407WFP-HC - BeHardware
>> Miscellaneous >> Monitors

Written by Vincent Alzieu

Published on October 2, 2007

URL: http://www.behardware.com/art/lire/686/


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The Dell 2407WFP-HC, the new star?

The Dell 2407WFP-HC, the new star ?

Dell changes its star screen, the 2407WFP-HC ! A hurrah is heardÖin some but not all countries. In the USA, everything is just fine. 669 dollars for the new generation 24 inch or 488 Euros taxes not included. Buyers can rejoice. Even if we add the French VAT of 19.6% by being honest at the border with customs, the total cost would be 583 Euros Ė an entirely competitive price with other current 24 inch offers by Iiyama, Belinea, and HyundaÔ. Except the 2407WFP-HCís ergonomics are in another class as it's vertically adjustable, can be pivoted and has card players and an integrated USB hub. Also, even if its design wasnít revised it is still very attractive.

In France though, we have good reason to make a sour face because Dell launched its star screen for 981 Euros. Sometimes it can be found on sale for 735 Euros. So why such a difference and can it be negotiated down?

There was talk of being able to negotiate a discount with Dell and so we contacted their sales service. However, they appeared reticent. It was impossible to get the smallest price reduction (besides with larger orders) even at the time when the screen is offered at its highest price, which was the case when writing this article. On the phone, representatives are very courteous and yes they are aware of the difference in price. By the way, this is also valid for all accessories for sale on Dellís website. However, she explained that this was due to the differences in living standards (?!?). The US has somehow been relegated to developing country status without any one telling us.

The only good news from our telephone enquiry was that we learned Dell would continue its (irritating) habit of promotional pricing. At times the monitor will at a high of 981 Euros and other times on sale at 25 % less or 736 Euros. This was the price of the previous version, the 2407WFP, at the end of its life.
From the Dell 2407WFP to the 2407WFP-HC
Launched in June 2006 at an initial price of 1159 Euros, the 2407WFP is now replaced by its clone except with two letters more and an additional technological detail.


The Dell 2407WFP-HC is strictly identical to the previous version except its backlighting, which has been replaced by a new wide gamut system. The light which is now emitted, enables the screen to attain colors which were formerly inaccessible on previous versions. Normally, this represents two major improvements :

from a theoretical point of view, those who work professionally with images with their digital reflex, printers, photo editing software, and who want to go from the sRGB color space to Adobe RGB or NTSC can now display the real colors of an image on the screen. Itís an essential point because a printerís color space is noticeably larger than that of traditional monitors. And for this reason, an image on paper can be significantly different from what is seen on a screen. For example, if we are going to print thousands of catalogues with sweaters, itís best to display the actual red that clients are going to receive. If not, there could be potential significant returns.

From a practical point of view, itís been shown that wide gamut screens tend to offer better color gradations in movies. This most often involves 8 bit screens like sRGBs with the same input signals. It is an unexpected improvement but itís there Ė in not all but in most cases. It can also possibly be explained by the fact that wide gamut monitors and therefore the circuitry is more recent than sRGB versions, which means that image processing algorithms may have been reviewed and improved. This benefit is therefore not necessarily related to wide gamut technology, but it can often be associated. The potential improvement then involves all users and not just professionals, because these Full HD 24íís can adeptly display ADSL TV (with an HDMI/DVI cable, for example), DVDs, or even better, HD in BluRay, HD-DVD or VOD.
The tests
We run tests for reaction time in games, delay of display, and video rendering (SD, HD 720p, HD 1080p). We also evaluate ergonomics, viewing angles, the quality of upscaling, and the panel's brightness homogeneity. In short, we look at all aspects of a screen.

For color fidelity we use the LaCie Blue Eye Pro colorimeter, based on the Gretag tool and coupled with the new LaCie software suite. More evolved than the previous version, this helps us to compare a monitorís display quality (color spectrum and DeltaE) in standard settings and after calibration. Results are sometimes surprising as itís often best to take the time to manually adjust colors (or at least contrast, brightness and color temperature).
The results of our study of 18 patches makes it possible to create a table visually resituating the variation of colors compared to an ideal grey scale.

Rather than a response time measurement with an oscilloscope, we photograph the monitor in action. This is an effective way of capturing afterglow. The program used is Pixel Persistence Analyzer r (PixPerAn for short). Pictures showing these ghosting effects are captured with a Canon 350D at a shutter speed of 1/1000 s. We take 50 pictures in burst mode for each test to precisely measure the progression of afterglow between images. Otherwise, we haven't given up on the practical tests in games, HD and DVD video, web surfing, etc.
Finally, we measure the delay to display images compared to CRT monitors.

The test computer is self-assembled, has an AMD Athlon 64 3500+ processor and NVIDIA GeForce 7900 GTX card


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Ergonomics, brightness homogeneity

Ergonomics
Nothing changes between the 2407WFP-HC and previous classic gamut 2407WFP. The bezel is strictly the same as well as the PVA liquid crystal technology. This is unfortunate because with the newest 2707WFP (also a wide gamut) Dell chose to include some metal on its bezel. At the same time we are quickly consoled by the design and ergonomics that we liked so much on the previous version: vertically adjustable base, can be pivoted, has card players on the edge of the screen, and a 4 port USB hub.

Here are the various positions we can put this screen into:

Brightness homogeneity
In this test, the monitor is set to display a brightness in white of 200 cd/m≤. We then display a white image and measure the actual brightness on various points of the panel in order to detect potential differences:


The 2407WFP-HCís brightness homogeneity is particularly good except for a high in the upper right hand corner and luckily not really noticeable without the sensor.

Overall, this result is better than average as most LCDs normally display a difference of 30% between the brightest and darkest point on the screen.


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Input lag in games

2407WFP-HC : Input lag in games
If you didnít already know, almost all LCD monitors have a small delay in display. To measure this, we photograph a chronometer which is precise to 1/1000th of a second displayed in clone mode on our reference CRT and the LCD we are testing. We take 12 consecutive differences, eliminating the two extremes and then find the average delay. The most reactive model measured up until now is the 22 inch Iiyama ProLite E2201W, which had no delay on our 12 measurements. Normally, we find a delay between 10 and 30 ms on most screens.

For this test, we deactivate graphic card / screen synchronization to capture a more precise delay instead a value that is rounded to the nearest image. For this reason, the resulting measurements are not dependent upon the fps value. An LCD functions at 60 Hz (even those that claim 75 Hz) and so a delay of 17 ms equals an average delay of a single image. In the same way, 33 ms equals 2 images. This may not seem like much, however, to an on-line gamer it could make a world of difference and, for example, an adversary with an LCD or CRT will see his character two images before him. This can be compounded by the fact that the mouse can add another 1 to 8 ms (except very poor ones), and the graphic card adds a half image delay (at best and actually this can be 5 to 50 ms). More specifically in our research we found that this can result in a total delay of 110 ms or 6.5 images. In this case, it is indeed noticeable and even bothersome for some gamers. For more details on this subject, see our article on LCDs images delayed compared to CRTs ? Yes ! .

This test applied to the Dell 2407WFP-HC and its rivals resulted in the following graphs :


PVA 6 ms : Dell 2407WFP-HC



TN 3 ms : Iiyama Prolite B2403WS


PVA 6 ms : Samsung SyncMaster 245T


MVA 8 ms : ViewSonic VX2435wm

The input lag measured on these large monitors isnít that noteworthy. As we will see in on the next page, reactivity is satisfactory and all (at least the more recent versions) have a delay of between 2 to 4 images. Unfortunately, these results are rather stable.


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Reactivity tests

Reactivity tests

Hereís the concept in this test: A car moves from right to left at high speed. The movement isnít perfectly fluid and depending on its speed, the car is shown in several successive positions. When this process is sped up, the car goes very fast, positions are very close and the eye perceives a fluid movement.

the perfect screen
a screen with 2 afterglow images

A monitor without ghosting effects would have previous images completely fading away when a new one appears. This is ideal, however in practice, it's often not the case as images progressively fade. Sometimes up to 5 afterglow artifacts remain on the screen representing the visible white trail behind objects.

We capture this LCD defect with a camera at a shutter speed of 1/1000 s by taking 50 pictures per test. We then can see a monitorís ghosting effects, or the carís position in the entire process from the moment when afterglow is at its maximum, up until when the next image is about to be created and the previous image is the least visible.

Here are the two extreme states between which each monitorís afterglow can oscillate.

S-PVA 6 ms : Dell 2407WFP-HC

Letís go directly to results. There is strictly no improvement in reactivity compared to the previous version and this screen is not slower or faster that other PVAs or MVAs. On the other hand, even if it isnít immediately obvious, the Iiyama ProLite B2403WS, a TN 3 ms, is slightly more reactive in games in clone mode side by side with this Dell. Itís very subtle, but if we had to pick a winner the prize would go to Iiyama.

But can we play fast games on this Dell 2407WFP-HC? It depends less on the screen, sufficiently reactive for us, and more on your graphic card because managing 1920 x 1200 pixels is very heavy.

To respond to an issue brought up in the forum: Is the 2407WFP-HC subject to a particular ghosting or bleeding, an especially poor RTC (overdrive), or even the display of ill-timed blue, green or red lines ? No, we didnít note any of this. "Our" 2407WFP-HC showed entirely normal behavior and is, in our opinion, representative of screens found in stores. Or in other words, its display is identical Ė in terms of reactivity Ė to the previous 2407WFP.

Here is the reactivity of its main competitors :

S-PVA 6 ms : Dell 2407WFP

TN 3 ms : Iiyama Prolite B2403WS, with the OD set to 2

TN 5 ms : Samsung SyncMaster 245B

PVA 6 ms : Samsung SyncMaster 245T

P-MVA 8 ms : ViewSonic VX2435wm

TN 2 ms : Samsung SyncMaster 226BW S series



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Color rendering

Color rendering
The Dell 2407WFP-HC is a wide gamut screen. From our past experience, this characteristic generates more fear than excitement for us. The Samsung monitors we have tested often rendered bizarre colors that were impossible to adjust or even calibrate. On the 226CW and 245T, this meant reds with an extreme vividness and an absolutely unnatural appearance.

Even before we put the 2407WFP-HC under the colorimeter, we started with a practical test. For several months now, Iíve been using a 2407WFP v4 that is calibrated. We changed it back to its standard profile in sRGB and put the new screen in its place.

Actually, the transition was easy and the quality of images was unaffected. For this reason and in the following more objective test with our colorimeter, we saw that color fidelity was good from the start. The Dell 2407WFP-HC is the first wide gamut screen with this appreciable characteristic and the sensor even confirms its gamut has indeed been extended. As you can see, we donít always have to accept ultra-saturated colors on monitors.

Tests and measurements

As usual with the help of our probe we measured the difference between ideal colors and the ones actually displayed on the screen giving us a value called average DeltaE 94. We understand this data from our experience in this domain, however, this isnít the case for everyone. We therefore are putting into place a new notation system based on our measurements, and which will immediately give you a better notion of quality in this area. Currently, there are no standards for color fidelity and manufacturers can pretty much say and do what they like (see the saga of the Samsung 226BW...). This system will only be for our website but at least it will be a step in the right direction.

By taking the differences between the measured colors and actual gamut found on the screen, a grade from A+ to F- will be given (and less if necessary). Of course, the higher up in the alphabet, the better the color fidelity. An A+ monitor will necessarily be factory pre-calibrated with an average DeltaE of less than 2 and with an extended gamut. Applied to current 24 inch products, this result in the following:

Color class fidelity

This new Dell does slightly less well here than its previous version. The former v4 had an average dE of 2.3 and the new is at 3.6. Itís still an excellent result and one of the best but color fidelity is a trifle below its predecessor.

The table above does not replace the usual detailed explanations. For those who are interested, here is the normal analysis of results. (Please note this time that the panel homogeneity section is found on the page devoted to each screen.)

The quality of colors is measured with the LaCie BlueEye Pro colorimeter, which in fact, is a Gretag colorimeter coupled to the software suite developed by LaCie.

Just to remind you, we work with a value called DeltaE. It represents a measurement between the color requested and the one really displayed on the monitor. The higher the result obtained, the less true colors are. More precisely, here is how to interpret the graphs:
- Delta E > 3 : the desired color is noticeably different from the one on the screen.
- 2 < Delta E < 3 : color quality is satisfactory, but a graphic designer probably wouldnít be content
- 1 < Delta E < 2 : colors are accurate.
- Delta E < 1 : the result is perfect.

DeltaE by default


You may have noticed that results are consistent with the grades above, and you can see that "A"s were given to screens with a starting average dE less than 2.5.

Besides color rendering, there is a point that concerns more and more people, depth of black. We measured a constant brightness of 200 cd/m≤ in white.

Depth of black (cd/m≤) with white at 200 cd/m≤


The Dell 2407WFP-HC surprisingly wins the title for the screen with the deepest black, formerly held by a TN. Normally, PVAs are the champions in this category and so the former order is re-established.
Most monitors are under the 0.30 cd/m≤ mark and so are at least satisfactory in this domain. The above measurements result in the following contrast ratios:

Contrast ratio measured at 200 cd/m≤ in white (xxx:1)



Each time, we analyze 18 color patches and 16 of these results are given in the following graphs:

PVA 6 ms : Dell 2407WFP-HC

Contrary to the Samsung 245T, not only is the 2407WFP-HC well adjusted when we take it out of the box, but also there is no color dominance Ė except in blue. However, as we will explain in the following page, the actual effect of this is minimal (even nil) because the eye is much less sensitive at this spectrum than in grays, for example. To illustrate this point, on the left are the desired colors and on the right those produced by the screen:


As you can see, the intensity of blue is noticeably different, however, it remains blue. Itís not like a gray that has pink hues and which can actually be bothersome. Therefore, there are still some surprises in terms of colors for this screen, however, nothing too excessive and its more in the extreme shades.

Our conclusion is that overall color rendering is sufficiently natural! However, fidelity is slightly less than on the previous v4 Dell we tested. This is still the best result weíve obtained on a wide gamut, with a small reservation on the preset black level.


PVA 6 ms : Dell 2407WFP rev.4


TN 3 ms : Iiyama Prolite B2403WS


TN 5 ms : Samsung SyncMaster 245B


PVA 6 ms : Samsung SyncMaster 245T


MVA 8 ms : ViewSonic VX2435wm


Right out of the box, the 2407WFP-HC is quite bright and close to 300 cd/m≤. At this level, black was measured at 0.40 cd/m≤ and we didnít need our colorimeter to see that it was washed out. We preferred to adjust brightness to a more reasonable value and opted for 200 cd/m≤. This is obviously brighter than a CRT, but itís comfortable and correct for all types of uses (games, movies, office, photo...) for an LCD. Going down 30% in brightness leads to a 50% reduction in the level of black and in our case this meant a final value of 0.21 cd/m≤. Or in the end, quite simply superb contrast!

To answer a reoccurring question: to calibrate a screen, is it always necessary to use a calibration probe. Modifying parameters in the OSD is a simple adjustment and often not enough, because differences vary from one color to the next. If we have too much blue in lighter shades, we can have too much red in darker ones, or vice versa. So, when we decrease the amount of red this affects all colors, whether they have too much or not. We are only changing color balances and putting dominances somewhere else. On the other hand, hardware calibration rewrites the entire color table that is used by the graphic card. Itís better but is more expensive. A good probe will cost 300 Euros and for this reason, we largely prefer when screens are factory pre-calibrated.


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Grey rendering

More concretely for grey renderingÖ
Unless you are an expert in monitors (and even then) it is difficult to imagine what these differences can represent. What is the most bothersome, however, is when we can immediately see color dominances on the screen. This can affect all colors but is particularly noticeable in grays where the eye can quickly see when blues or reds are overrepresented.

Here are the screenís grays and reproduced as measured by our sensor. For comparison on the bottom line are the ideal grays.

Whether the screen you are currently using is calibrated or not, you should be able to see the differences between the two lines.

PVA 6 ms : Dell 2407WFP-HC

As we can see, gray rendering is very good and well balanced on the Dell 2407WFP-HC. This compensates for the raw average DeltaE result, which was slightly disappointing. So in the end, we found this very good (see below for more details).


PVA 6 ms : Dell 2407WFP rev.4


TN 3 ms : Iiyama Prolite B2403WS


TN 5 ms : Samsung SyncMaster 245B


PVA 6 ms : Samsung SyncMaster 245T


MVA 8 ms : ViewSonic VX2435wm

You may recall that the DeltaE is in fact the DeltaC but weighted with a factor that is supposed to represent human eye sensitivity. More specifically, the colorimeter measures the gross difference between the desired color and the one actually displayed by the screen. It then applies a coefficient in function to the fact that our eyes are more sensitive to differences in grays than, for example, in dark reds.

This method is more precise and more representative of reality, however, itís still not ideal. From our experience :
In grays : DeltaE < 2 = is very good. dE < 3 : correct. dE > 3 : bothersome and most people will see color dominances.
In red, green, blue, cyan, magenta, and yellow the eye seems much less sensitive to variations and even with a dE of 6, we sometimes canít see the difference.
In lighter and pastel colors, the eye is more sensitive than with darker hues. When dE > 3 we can see differences that can be bothersome.

If we take the 2407WFP-HCís graph from the previous page:


Grays are barely above dE = 2, extreme colors are sometimes above 6 but most are around 4, and lighter colors are at 3.

In our opinion, even those who are particularly concerned with color fidelity ought to be satisfied with this screen.


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Extended gamut

Gamut: finally a good wide gamut

PVA 6 ms : Dell 2407WFP-HC


Classic sRGB screens : Iiyama, Dell, Samsung...


PVA 6 ms : Samsung SyncMaster 245T


After several months of suspense, the price of the Samsung 245T has finally fallen (or soon will) to 1000 Euros. When on sale, the Dell will therefore be more affordable.

As we can see on this graph, Dell and Samsung are equivalent in terms of gamut, closely sticking to each other. When we know that Dell also has better presettings and ergonomics, clearly the 2407WFP-HC has our preference.

We again realize that this is the first time we have a wide gamut with good colors on our desktop. Up until now, reds were particularly a problem in that they were too vivid, saturated and entirely unnatural. Here this isnít the case. We do have a blue that with large DeltaE values, however, in practice this isnít dramatic. The colorimeter would probably find bloated values in extreme shades but the screen displays a natural rendering and no single color stands out.

There is one thing lacking on this monitor most likely related to the fact that itís not a new screen but rather based on a former version. There is no button to simply go from wide gamut to sRGB. This isnít really lacking in terms of the general display of photos, but more to insure us that photos taken in sRGB arenít distorted.


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Viewing angles

Viewing angles
We take pictures of the monitors from a 50į angle from all sides. The claimed viewing angles in a productís characteristics are often exaggerated.

There are three types of technology to choose from: TN, MVA and PVA, the last two being closely related. For comparison, we added an IPS, the Dell 3007WFP HC. If you are a regular reader of our LCD surveys, you wonít be surprised by results, which are entirely normal.

First of all, for lateral viewing angles the IPS is by far the best. If this is the most important criteria for you, this is the type of technology you need. In second place comes the 245B, a TN panel. In the past (2 years ago), TNs were rather catastrophic from the side angles. Now, it is possible for several people to share a screen even if they arenít perfectly in front of it. Finally, we have the PVAs and MVAs, which are equal. Beyond 40į from both sides, there is a loss of contrast, which however isnít too extreme. In fact, there are only really problems when looked from below.

Vertical viewing angles : The IPS screen always offers an image that is almost perfect at 50į and even beyond. In this area, other technologies are largely inferior. The PVAs are behind with a rather abrupt loss of contrast with an image that is still visible though not as flattering (black is more gray, white is pale, loss of depth). Itís the same but even more sudden with MVA panels. Finally, we have the TN screen. From above, the image loses all of its contrast. From below, it turns black. This complicates things when you want to use this screen as a TV and depending on the size of viewers, the monitor may have to be inclined.


PVA 6 ms : Dell 2407WFP-HC

This rendering is entirely typical of PVAs. The image is nice directly in front of the screen. Viewing angles are rather open with a noticeable loss of contrast from all directions. However, the image doesnít turn black or wash out. This PVA is well suited for a dual monitor configuration even with a second very large screen.


PVA 6 ms : Dell 2407WFP rev.4


TN 3 ms : Iiyama Prolite B2403WS


TN 5 ms : Samsung SyncMaster 245B


PVA 6 ms : Samsung SyncMaster 245T


MVA 8 ms : ViewSonic VX2435wm


IPS 6 ms : Dell 3007WFP HC



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Rendering in movies

Rendering in movies

Full HD + wide gamut... With televisions when we connect an HD source (Bluray or HD-DVD player), the combination can be amazing. There is exceptional sharpness, vivid colors, and often perfect gradations.

Unfortunately, with monitors itís another story. At the moment, none are equipped with image correction circuitry, and we have to rely on a few functions offered by graphic cards to reduce the undesirable side effects of MPEG compression and video noise. Also, monitors are almost all subject to solarization, in other words, blocks of uniform color where we should see a superb gradations. This Dell screen doesnít set itself apart here and it also shimmers as much as the others.

In short, its wide gamut doesnít improve anything in this domain and it only changes the rendering of some colors. For example, certain blues have a purple tinge. This is probably closer to what the camera actually captured but much less beneficial than noise and compression correction circuitry.

On the other hand, in movies we did appreciate its open viewing angles. This is a defect of TNs like the last Iiyama we tested where the screen will turn black when we lean back on couch. At least this 2407WFP-HC doesnít have this problem, however, we suggest you better adjust your graphic card to minimize the effects on video (see our article ATI and NVIDIA correct the LCD shimmering in movies).


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Conclusion

Conclusion

So is the Dell 2407WFP-HC:

- better than the previous 2407WFP ?
Yes. Color fidelity is, according to the colorimeter, slightly inferior to the rev 4 of the 2407WFP we recently tested, but to the naked eye itís not obvious. But those who can really gain from this screen are users equipped with high-end reflexes that go outside of the sRGB color space. In movies as well, there is a gain with slightly truer tones;

- the current 24 inch to buy? Not necessarily. First of all, DONíT BUY IT at the high price of 980 Euros because it can sometimes be found for 735 Euros. After this, not everyone will prefer this screen to its rivals. 2 and 3 ms TNs are a little more reactive in games while MVA panels shimmer less in movies.

- affected by bleeding, ghosting, dark phantom images related to a poor overdrive or subject to the display of colored lines. This was described by a first few users of this monitor mainly on US websites. However, as we showed in the section on reactivity, our 2407WFP-HC has entirely standard behavior in all areas and there was nothing abnormal to report on these points in tests. And actually this was to the contrary, because the overdrive functioned particularly well with a reactivity comparable to the fastest TN screens.

At this point, afterglow is less related to the liquid crystals themselves than the natural retinal persistence in our eyes. This is due to the exposure of bright images for a relatively long period of time (1/60th of a second, without a transition to black between images, contrary to how CRTs function). We have high hopes with technologies that are starting to appear with Samsung and BenQ, respectively called MPA and BFI, and which are trying to remedy and even eliminate this problem. Unfortunately, this ę artificial sweeping Ľ currently causes more problems than it solves and MPA revealed to be quite simply useless. Moreover, after two years of highlighting this future technology at the CeBIT, Samsung finally launched its first MPA, the recently tested 245T, without even mentioning this aspect in the monitorís characteristics! As for BenQ, BFI was introduced with a number of revisions compared to what it originally should have been. From the insertion of black images, they finally arrived at a backlighting system (at a doubled frequency compared to Samsung, and therefore better efficiency, in our opinion) and reactivity does improve Ė though only slightly. However, too much is lost in brightness homogeneity and comfort and we outright suggest you deactivate this function. In the end, for those who want the best reactivity for 24 inches, choose the Iiyama ProLite B2403WS. Then again, the Dell 2407WFP-HC does almost as well with wider viewing angles.


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