Copied from DPT Homepage:

Dead pixel tester with display aids and illusions.

DPTDead Pixel Tester, with display tests.
TFT screens have thousands of pixels, on a 1024x768 monitor, there are three cells for each pixel - one each for red, green, and blue - which amounts to nearly 2.4 million cells (1024x768x 3 = 2,359,296). 
There's only a slim chance that all of these will be perfect; more likely, some will be stuck on (creating a "bright" defect) or dead (resulting in a "dark" defect). DPT was written to help me check my own screens (Couldn't find one that worked across multiple desktops so had to write my own!) by cycling through the three primary colours used (red,green,blue) and all on (white) and all off (black).

Basic usage

1) Ensure your screen is free from dirt and marks, if possible clean it with correct recommended products.
2) Make sure your screen resolutions are correct for your monitor, e.g. if your screen is 1680x1050, make sure the resolution for that monitor is set at 1680x1050.
3) Use the right mouse button to toggle the main menu on and off, so that you can see the whole screen without any interference.
4) Use the left mouse button to toggle through the basic application colours of Black (Check for stuck on pixels), Blue (Check for dead blue pixels), Red (Check for dead red pixels), Green (Check for dead green pixels), and White (Check for dead pixel group)
5) Each time you select a new colour, scan your screen carefully looking for defects (Black spots will be dead pixels on any colour screen)
6) Use the [M] key to toggle a Marker at any suspect point on the screen.
This allows you to scan the rest of the screen and come back to that area/check the screen is clean. Hint : After placing a Marker you can move about to check if the pixel moves in the area or not. If it does not move then it is most likely a dead pixel, if it does move then it is probably a mark on the outside of the screen.

Why do I need/would want to use this program?

In most cases, a stuck or dead pixel is impossible to fix (some people rub them gently with a cloth etc. search the net for other ways), however most manufacturers have a policy which will specify that after X amount of dead/stuck pixels they will replace the screen free of charge (in warranty period).
You can use DPT to help identify IF you have any pixels and how many in order to see if you qualify for a replacement screen/laptop... no guarantees though!

Usage


DPT mainscreen


* Move the window by grabbing the border at any location

* The [x] in the top right hand corner hides the screen, you can also use Right mouse button or [ESC]

* Click the www.dps.uk.com text to visit our site

* Left mouse click :
Cycles though the basic colours Red, Green, Blue, Black and White

* Middle mouse click : Toggles the mouse cursor on and off, scrolling the wheel changes the display pattern

* Right mouse click : Shows and Hides the Main Menu

* Pattern selection: Toggles between a solid colour on the screen and a selection of patterns (also display utilities). All the patterns are 1 pixel wide to help make spotting dead pixels easier. The secondary colour (off color) can be chosen via the Direct Colour Selection

* Markers : New in version 2.50+ is a small marker function.
Where ever the mouse currently is, press the [M] key and a small circle will be drawn at this point. This allows you to move your focus, clean the screen and easily find the position again. You can remove the marker by simply placing the mouse back in to that position and pressing [M] again, or use [R] to remove all the markers on the screen.

* Auto Cycle : Automatically colour cycles as if you where pressing the mouse button. Next to this you can change the speed at which this occurs in milliseconds (1000ms=1second)

* Help/Info : Brings up another moveable window with basic help

o About
o Move the window by grabbing the border at any location
o Close the window by clicking on the [x] in the top right corner
o Click the small display icon next to point 2 to bring up the Display Properties/Setting tab screen.


* Colour selector : Turns on and off the direct colour selection form, can be toggled with the [S] key (see below)

o  Colour selection
o Move the window by grabbing the border at any location
o Close the the window by clicking the [x] in the top right corner
o Left mouse button : Selects the main colour to be displayed
o Right mouse button : Selects the secondary colour to be displayed when using hash (this will be automatically turned on if it is not on already)
o Colour selector : Pops up the standard colour defining screen where you can pick or make any colour to use.

* Exerciser : There has been some talk on the web of a video that can cure stuck pixels on the PSP, which works by rapidly changing the colour of the pixels.
I can not verify or deny if this works, but for fun I wrote my own pixel exerciser. This will bring up another moveable window, that you can put over the stuck pixel(s) which will randomly change the colour of the pixel.
Different places say different things on the effectiveness of this, but most leave it running for several hours before they see a result.
If this does work for you then please send a donation :) and an email so I can post any results. The speed of this and colours shown has been improved in version 2.50+ and you can now use [E] to start a new Exerciser.

o Pixel exerciser
o Move the window by grabbing the border at any location
o Close the window by moving to the top right hand border, the cursor will change to an [X] showing that a click will close this window.
o Resize the window by moving to the bottom right hand border, the cursor will change to a NW/SE arrow to indicate the mouse will resize at this point

* Exit : DPT : Closes this application, before you close please take a look at our sponsors!!

* Main colour : Shows you the current colour selected

* Pattern colour : Shows you the secondary colour you currently have selected (from the Direct colour selector, using the secondary mouse button) 

* Left arrow : Move to the previous sponsor advert if it took your fancy!

* Information : Basic information on your current screen resolution.

* Right arrow : Move to the next sponsor advert, allowing you to see the offers


What does this program NOT do?

* AUTOMATICALLY POINT OUT YOUR DEAD PIXELS - this is physically impossible for any application to do, all this program does is display colours and grids to try and help you identify dead/stuck pixels. Use the Markers to help find them and make sure your screen is not dirty.

* Contact the web or send ANY information or store any information
(In fact you can run it directly off a USB disk or floppy even!) 


Additional information

By changing the pattern to vertical/horizontal lines and the hash patterns it is easier to see dead pixels as well. The hash pattern does not work very well on monitors that are connected via analogue, unless they have been very well set up.

Just for fun I've added 5 different illusions patterns, some of these work better than others, but are great fun to see:-

* Black dots : A series of white dots connected with grey lines, but there looks like there are black dots in the white dots

* Spinning circles : When you move your eyes, the circles appear to spin

* Cafe wall : Spotted in a cafe, the grey horizontal lines appear to bend, not be straight

* Solid grey bar : By having a gradient colour in the background, the grey main bar in the middle appears to also have a gradient effect, but it is in fact only one colour.

* Wazes : Again when you move your eyes the pattern appears to be moving in waves, freaky!

There is also a host of other Patterns that allow you to check the saturation / Intensity and so forth of your screen. You are better off using your manufacturers tools or a screen calibration tool.


Comments from the uploader (olofolleola4):
Here are some information from the author of this great freeware program:

"We are hoping this year the the number of downloads for DPT will exceed 1 million directly via our website. In truth this target has long since gone as third part redirects tend to download the file directly from us, and also DPT is on the cover CD/DVD of magazines around the world now. However we are eagerly anticipating the 1,000,000 download of DPT some time this year :) 
Becasue DPT earns us no revenues, and donations are few and far between, we have added a couple of small sponsor banner adverts into the application now, and we hope that these are of some interest to you."

With that in mind, here are the links to donation and the direct download from the homepage.

Donation to Data Product Services: 
http://www.dataproductservices.com/donate?Item=Dead%20Pixel%20Tester

Direct download link from the Homepage:
http://www.dps.uk.com/download.php?file=4