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  • ikomu Level 1 Level 1

    Can I ask your thoughts about Samsung display over LG  ? Colour&contrast etc. cos IR is not affecting me unless I carefully check it on certain conditions but lately I've read some poor comments about samsung screens i.e Dead pixels,yellow tint,Lower contrast and poorer colours compare to LG and started to worry about loosing vivid colours and perfect contrast and black levels of LG display (SJA1)

    Thanx in advance

  • brianjsw Level 1 Level 1

    I'm not Jajaba, but having just been though the wringer on this, here's my advice:


    1)  If IR is not bothering you today, keep what you've got

    2)  If you look for IR and have IR, keep what you've got -- unless it actually begins to bother you during normal use

    3)  If the IR truly becomes bothersome, go for a replacement

    4)  Be aware that no panel is identical, and very few would pass muster for what we think we should be getting for $3000.  I understand they exist, but I haven't seen one of them yet.

    5)  In general, colors, brightness, etc seem to vary by panel, and better/worse isn't a common characteristic of all panels from any of these manufacturers.  The only issue that's common to one manfufacturer is the IR.


    I've got a Samsung.  It is NOT perfect.  It's got the shadow issue in the middle of the screen.  Funny thing is that on another thread a guy posted a picture and the shadow is in the exact same spot.In fact, if it weren't for the fact that every retina panel I've been "treated" with has been defective in my opinion, I'd return this one too.  But the bottom line is that Retina panels are not ready for mass production yet so once you find one you can live with, hold onto it!


    Good luck.

  • ikomu Level 1 Level 1

    Thanx very much for your kind Reply, Thats what exactly Im worrying about I can only see retention on Gray backround If I make test other than that its all perfect no colour tint,dead pixel ,Vertical line ,perfect black...

    It seems a bit risky to me to change the panel ,what If I lost what Ive got or even worst ;Yellow tint ,vertical line ,shadow white leak etc.

    I believe SJA2 is the best display so far ,I may Live with SJA1...


  • Jajaba Level 1 Level 1

    I think you hit all the rarely recurring issues with the Samsungs.  Assuming you don't get one with the obvious issues of dead pixels or yellow areas on screen then the only significant difference, in my opinion, is the contrast ratio.  Our LG's average 1000:1 versus 800:1 on the Samy's.  After calibration (using Xrite i1diplay pro) they both look very similar when side by side.  I think the higher contrast on the LG is why people think the LG colors seem more vibrant, the darker blacks seem to make the color 'pop' more onscreen.  Both displays acheive virtually identical sRGB color gamut of ~ 96% after calibration.  One thing that is not commonly known is that lower contrast ratios are typically used when photo editing for printing.  We have our high gamut RGB monitors set to 600:1 - 700:1 which helps see fine shadow details when viewing at the low brightness levels used for print editing.  

  • ikomu Level 1 Level 1

    Now things are getting more confusing for me

    your LGs might be SJA2 and I believe they are the best...

    I dont know what to do

    Ive got extended apple care till Dec. 2015 but I got rmbp used from computer shop and havent got the receipt for apple care , I guess I cant use that without receipt is that right?

  • Jajaba Level 1 Level 1

    If you have Applecare it would be on file with Apple under your serial number and / or registration.


    All 4 of our LG's are SJA1's.

  • Chuck Gould Level 1 Level 1

    Good feedback. Thanks.


    I agree - I'm extremely confident Apple is/was certainly well aware of the technology and evaluated displays thoroughly before committing to a manufacturing run.


    CCFL's: it's been 5 years since I've had a MBP with CCFL backlighting and I'm so glad I don't have to wait for that warmup anymore. I do have one small CCFL display left on my amateur radio that seems to take forever to come up to room level brightness. As far as temperature effects from the tubes, it seems to me they would be localized to the areas near them. If there were any LCD artifacts, they would be along the backlight edges.


    When the rMBP's CPU gets hot, there's not much way for the heat to get to the display. It's good to know, though, that you haven't seen any adverse effects from the sun heating the display. That's the kind of info I was looking for.


    The reason I bring up temperature is it could still be a reason the display might become susceptible to image retention. I believe the Phillips paper is still applicable, though technology has greatly reduced the tendency towards IR on any display type (coincidentally, LG was LG Phillips until 2008).


    My understanding of IR is that it's caused by an electronic condition, rather than one of viscosity change. As temperature increases, the tendency for random electron movement (migration) increases - generally seen as noise, reduced efficiency, and some other effects that escape me at the moment... Anyway, a couple of examples would be telescope sensors and radio astronomy receivers. Both need to be cooled to cryogenic temperatures to keep noise at a minimum.


    Here's a quote from the Wikipedia article on image retention:


    The cause of this tendency is unclear. It might be due to accumulation of ionic impurities inside the LCD, electric charge building up near the electrodes,[1][2] parasitic capacitance,[3] or "a DC voltage component that occurs unavoidably in some display pixels owing to anisotropy in the dielectric constant of the liquid crystal".[4]


    Translated, it means the LC part of a (sub) pixel still thinks it has a charge - when in fact, the potential between electrodes has changed. Exactly how much of an effect high temperature has on this tendency is what I'm interested in. I'm going to try and do some further research and see if I can find some more technical papers on the subject, but I thought it worth a try to get at least some anecdotal data which could connect exposure to high temperatures (>113ºF/45ºC) with the tendency towards IR. It might help explain why there is an apparent delay in the onset of IR after a period of many months. Perhaps, this info could help allay some folk's fear about which display their new rMBP will be equiped with - and let those, who now have a perfect display, relax!.

  • Chuck Gould Level 1 Level 1

    (Correction - it's been 4 years since I bought my Early 2009 17" UB MBP with a LED display. Seems like it's been forever since I ditched CCFLs ;) )

  • Barry Fisher Level 3 Level 3

    Sorry bout the Win 8 machine. For me I can't think of any other note book I'd rather have than my current rrmbp, but if I didn't trust the current model rmbp I would certainly get the regular mbp.  How come you didn't go that route? 

  • DomdiDom Level 1 Level 1

    @Barry Fisher


    Well when I walked into the Apple store  in my city I walked in ready to buy a 17" regular one but the kid didn't have any, he said and really pushed the rmbp. Although I was mind set on the 17" size I quickly fell in love with rmbp on display. They didn't have any in stock either of course. I remember thinking, this is an Apple store isn't it?. So I spent 10-15 minutes getting my first mac lesson Anyway, from then on I only considered the rmbp as the retina I thought made up for the loss of 2". Not to mention ssd and latest tech for very little difference in price at the time. I don't know the difference in price as i write this. So in short, they didn't have either at the time. I didn't want a regular 15". I don't know that I would have bought the retina on the spot anyway as I like to read a little about what I'm buying first. That's how I found this thread. I don't even know if you can still get a 17" regular anymore but if you can, that's an option when/if the time comes to replace my series 9, assuming it's going to keep failing. If they have them at bb that is.

  • Jajaba Level 1 Level 1



    You must not be aware that both the CPU and GPU heatsinks are cooled via the dual fans through the dual vents located along the full length of the hinge.  All the heat produced during heavy loads is blown directly along the lower front edge of the display.  When I do large batch process files which load the CPU to 100% on each core (90-100C) and the GPU is running at 70-80C, both the fans are at maximum RPM for the duration (2-3 hours) and the warmest place on my MBPr is the lower face of the display and the upper center of keyboard (T,Y,5,6,7 keys).  The lower left side is warmer than the right as the CPU vents on the left and it produces significantly more heat than the GPU.  I know my display in these area is much warmer than the 45C you mention during our daily batch file processing.  So I think this debunks your theory that area specific heat has an effect on IR, if that were the case it would mean that the most affected areas should be along the lower portion of the display.  I have not read any reports or posts that indicate IR is not basically uniform on the whole display, also all the checkerboard test images showing IR that I've seen show mostly uniform IR, it's definately not worse on the edges or bottom of the display area.  I do recall several reports of Samy displays showing area specific yellowish tint on the lower left or right corners.


    Regarding the CCFL backlighting, the pro RGB displays we use are not edge lit.  The CCFL 'module' takes up about 2/3's of the back of the display area.  They are all 100% backlit mainly to control screen brightness uniformity.  As for the heat produced I just checked our NEC PA271W monitor specs and the "typical" power draw is 115 Watts.  That's the equivalent of having a 100 watt light bulb in less the a 1 cubic foot box attached directly to the back of the NEC's LG IPS display.  As I said before these monitors run very hot, much more so than the MBPr displays.  After they are on for a few hours the top vent area is to warm to rest your hand on it for more than a few seconds....


    Be caustious of what you find on wiki, there is a lot of false or misleading technical info posted there.  

  • oSBKo Level 1 Level 1

    Does anyone have a link to the test Apple would use to test for IR? or if not, an excact replica of it?


    Thanks in advance.

  • ikomu Level 1 Level 1


    3minutes test and black backround to see retention! (Which is not possible LOL )

  • Chuck Gould Level 1 Level 1

    Yes, I was aware of the exhaust port on unibody MacBook Pros. But the temperature of the air flow there is nowhere near 100ºC. If you use something like Hardware Monitor, you can see the temps reported by sensors on the heatsink itself, parts of the case top, etc.


    No, I haven't heard reports of IR near the bottom of the display. I also wasn't implying the 113ºF/45ºC was the cuttoff point beyond which there would be an effect. An engineering spec like that will have a large margin of "safety" before failure. I'm suggesting the temperature reached much higher temperatures, but as you point out, there isn't any good data (still will look further, though).


    I have no doubt those displays do get warm. Though, I haven't heard of any CCFL tubes which were flat. They sit next to flat material (essentially a flat light pipe) which diffuses the light across the back of the display. LED displays have the modules surrounding the display, but still use a diffuser panel. You can search for images on the structure of LCD panels to see what I'm describing.


    I used the Wiki quota as an example of what is thought to cause the charge storage in the LC. It's based on behavior known to be true in other materials. The description of anisotropic behavior in the LC is how LC functions. The structures in the LC align themselves with the electric field applied when controlling the pixel. The degree of alignment controls how much light passes based on the degree of polarization the alignment causes. This is true for TN and for IPS, except for the layout of the electrodes - horizontal (in plane) in the case of IPS. The quote supports my own electrical engineering knowledge, though displays are not my field of expertise (which doesn't mean I don't understand the underlying principles of them).


    I wholly agree Wiki isn't the end all of technical information. As with any article or paper, you have to also check for references - especially if the subject isn't in your own "knowledge base".


    I suppose I should have been more specific with my question. The best example I can think of would be temperatures reached in a closed, hot, vehicle - which can reach upwards of 140ºF. Whether that's enough to degrade or damage an LCD, remains to be seen (no pun intended). I may need to start a new thread somewhere that only addresses the question.

  • Chuck Gould Level 1 Level 1

    FYI: I got curious enough to go and measure the exhast temps (and the area around the vents). Although some air does blow upwards, most of the flow gets directed back under the hinge to the rear (measured with the down of a calibrated cockatoo feather ).


    Temps measured with all cores near 100% (converting video file).

    (15" mid-2012 MBP with Retina Display, 2.7 GHz, 16 MB RAM, 768 GB SSD)


    Fans at max of

    ~5928 RPM (L)

    ~5496 RPM (R)


    From Hardware Monitor:

    CPU A Proximity

    154º F / 68º C

    GPU Chip

    147º F / 64º C

    GPU Diode

    162º F / 72º C

    Main Heatsink 2

    122º F / 50º C

    Main Heatsink 3

    124º F / 51º C

    Platform Controller Hub

    145º F / 63º C


    Infrared thermometer measurements:

    Top Cover to rear of 4 key

    107º F / 41.7º C

    rear of the 7 key

    107.3º F / 41.8º C

    rear of the + key

    102.8º F / 39.3º C


    inside hinge from top (behind 4 key)

    103.4º F / 39.7º C

    behind hinge from rear (behind 1 key)

    102º F / 38.9º C

    behind hinge aimed down toward bottom

    behind 1 key

    109º F / 42.8º C

    right side

    103º F / 39.4º C


    hottest areas are behind (from rear) left and right sides of exhast vent (aligned with fans)


    hottest areas when aimed down from top at left and right sides (this is actually the metal where the hottest air is found - can't measure air with the infrared thermometer):


    128º F / 53.3º C


    115º F / 46.1º C


    display 1" up from lower edge


    98º F / 36.7º C


    96º F / 35.6 º C