Luminance Test Page Copy1

The general purpose of doing these tests – and any follow-up tests – is to ascertain whether installing new equipment with better bits (basically, expanded color gamut and higher dynamic range, though often simplified as HDR in many people’s minds) – will make a difference in existing rooms. There are many ways to look at this, but we have tried to develop a series that is fairly quick at determining a cinema-centric set of criteria.

This is not the document that will discuss all the details. This is the general order of things, the basics, and a portal to the checklists.

The Checklists [This will change as I have software that will weave all the parts together while still allowing the test team to send the data in chunks before going to the next room.]


The Quick ToDo:

0a) If at all possible, get a pre-report from the facility that includes all the screens sizes of the auditoriums to be tested, as well as the projector and media player (SMS or IMB) info  — including, if possible, the make and model, and the firmware/software state of each.
0b) Always try to get the materials ingested and the playlist created before the testing day. Until you have to sit there waiting for 30 minutes in each room, you will not appreciate this point.

1a) Note on the first page if your measurements are feet/inches or meters.

2a) Measure screen width and note in space provided.
2b) Note if Screen is Flat (Fixed Width) or Scope (Fixed Height).
2c) The form will automatically calculate the dimension for 2 Scope Screen Heights back from the screen.

3a) Set up Test Equipment on tripod placed at that 2X Scope Screen Height position, centered to the left/right center of the screen.
3b) The device should be at above any seats by at least 10 centimeters, with the optimal height of 1.1 meters (43 inches) from the floor (but not blocked by the seat, of course).

4a) Load and play the Target DCP first on a separate Playlist. Play it first while ingesting the other materials and making the playlist. This gives the team something to prepare with during the ingest time. (Repeat: Always try to get the materials ingested the day before.)

5) Take all readings in Nits. The equipment setting will likely say: cd/m2

6) The pages of this report will automatically be sent to a spreadsheet when the Submit button at the bottom of each page is clicked. If you also want them sent to the other email addresses, please use the segments on the first page of the report form.

What you will need:

____ A tape measure to measure the screen. If at all possible, invest in a laser distance measuring tool.

____ A Photometer – a device that can read luminance in Candela per Square Meter (cd/m2), down to 0.001 cd/m2, which we will call “nits” from here on. You can get and use a fancy $35,000 Spectroradiometer, but be mindful that they usually take many (many many) minutes to get their exact measurements of black. You want something that will give accuracy, and speed. If you can go 3 zeros (down to 0.0001) with reasonably fast measurements, get that. Then you can impress people by saying, “Yes, we got readings in the .3 millinits.”

____ A tripod. By all means, don’t forget the tripod.

____ A long extension cord – You won’t need it unless you forget it.

A Brief Description of What Is Being Tested, And Why

There are 3 basic segments to this testing.

First is a general review of the room using the ISDCF SMPTE Compliance DCP. This DCP which displays an auditorium layout, then puts audio into each speaker of the room with an announcement of which speaker you should hear, while also putting subtitles on the screen. This report sheet will allow you to make a note of the details that you notice. This DCP is in Scope format.

The second prelude DCP is the ISDCF Framing Chart. It is used to note the general framing (all the arrow points should be showing), and general color and sharpness characteristics. You should be able to easily see all 10 black to white squares, you should see that the top row of DCI colors are not too saturated and the lower set (which look normal in the 709 color space) are a little off. You should see that the lines in the focus squares are sharp and in RGB alignment, faces appear normal. If your room is exceptionally well tuned, you will see at the top right and lower left a small white square in the larger dark square. It can even take on a bluish tint in the best of rooms.

The first set of the measuring charts is called the NATO 9Dice. It is built so that all 9 Dice spots combined equal 10% white and 90% black. The concept behind this and the following set is that the average luminance level of all combined frames of the typical movie is about 10%. So that is the condition that we want to measure in.

We will be testing the varying degree of the the white spots by first using a target to set your meter in the center of a series of spots, then turning off the target and measuring. You will also be measuring the black levels of the room by turning the house lights to the full and trailer levels, plus turning the dowser off and measuring these to get various contrast levels.

[For a technical description of the expectations and dimensions of all these slides, see the following link: _____.]

The second set of measuring charts is called the DCIC slide. The single spot is also comprised of white for 10% of the pixels of the screen. This spot is placed at the 25% and 75% points on the horizontal plane. We will go through a procedure that measures the white, but also the black level of the positions on each side.

There is also a 3D section that takes many of the same measurements.

Finally, there is a DCP filled with pictures that can walk your team’s eyes through real life contrast situations.

The Checklists are broken down as follows – which you can tell from the buttons above.

1st, a page that gathers general information of the facility.

2nd is a page that gathers general information about the auditoriums that are being tested…the type of equipment and the age of the lamps and things like that.

3rd and 4th is a set of 2D and 3D images that capture information for measuring the usable contrast of the auditorium.

5th, is the set of pictures described above.

This section is a test of new buttons and you should ignore it please. Unless you have advice or a comment or would like to volunteer as a programmer. Then, please please please: advise, comment and volunteer.


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