Best 7800 ProSystem Palettes - Why The Shift Matters...

[Trebor]

Download the palettes here [updated 8/30]: 2X7-PROSYSTEM_20130830.zip

 

The '2X7-PROSYSTEM' palettes (25.7 degrees --> 26.7 degress --> 27.7 degrees)...

 

NTSC:

 

PAL:

 

Why? Technically the phase shift of the 7800 is ~25.7; actually, 25.714 according to the math here... https://sites.google.com/site/atari7800wiki/rgb (Thank you Eric Ball).

 

The reality though is most (all?) 7800 systems fluctuate the phase shift higher as the system 'warms up'; additionally there is a variable resistor which also impacts the ultimate end results. The color references affected the most - and consequently most noticeable - are values E$ and F$.

 

At the 25.7 setting colors 1$ and F$ match near exact. To the naked eye they in fact look exact. According to the books this would be proper having a 180 degree color-burst resulting.

 

However, even a new system I obtained within the last year does not stay at that degree. There is a deviation from it, resulting in the shift going higher than 25.7 degrees. The question is how much greater do we go?

 

Simply stated, color F$ more realistically ends up between the hue of Color 1$ and 2$; darker than 1$, but lighter than 2$.

 

If we set the phase two degrees higher (27.7) we end up with colors E$ and F$ as a near exact match of colors 1$ and 2$. Some systems, including one of my own, phases this much and even higher (~28.7) over several hours (To the point where E$ and F$ fall in between 2$ and 3$ in hue - and most other values almost look like they have shifted a complete row (I.E. 8$ starts to look like a 9$, 9$ starts to look like a A$, etc.); but now that is swinging the pendulum too far in the other direction.

 

So, if 25.7 is technically accurate, but hardly remains the reality, and 27.7 brings too much of a phase shift to the palette, then a happy medium would be 26.7.

 

Setting the phase to 26.7 we obtain a color F$ that is in between the hues of color 1$ and 2$. MESS, in fact, has F$ documented (Thank you Dan Boris) as a 'light orange' range, whereas 1$ is a 'gold' range and 2$ is a 'orange' range. Additionally, we obtain light browns from 1$, while now having darker browns set under F$.

 

Looking at color E$ under the 26.7 setting, it falls right as a 'pea soup', the 'Linda Blair special', puke-ish green throughout; placing it in between a green and a brown color. Going back to 25.7 causes E$ to become a stronger green on the lower end, swinging the pendulum to 27.7 makes E$ a brown color.

 

The often noted intension is for the E$ range to fall between a green and a brown; it is arguably better achieved at 26.7.

 

The extensive work done in brightness, contrast, saturation with the literally hundreds of palettes created and viewed across half dozen displays, along with the input of the community, has helped achieved a nicely saturated and bright palette setting from the base values as shown above. That is easily adjusted and open to interpretation of course, so if you want something more/less saturated, brighter, etc...Just ask.

 

Additionally, the "BASE" palettes are being included for those who perhaps just want the base values and/or like to self-adjust saturation, brightness, contrast, etc.

 

BASE '2X7-PROSYSTEM' palettes (25.7 degrees --> 26.7 degrees --> 27.7 degrees)...

 

NTSC:

 

PAL:

Unlike the GCCFINAL palettes, we are not looking to factor in a wide range of television tints or pot adjustments. These palettes presumes a properly calibrated/pot adjusted 7800 and a television which falls within a neutral tint setting - and expects similar from the monitor it is being displayed upon.

 

It's almost a certainty that programming color choices were made on systems with a variety of phase settings as well. For instance, some games like Choplifter! and Midnight Mutants look better with a higher (27.7) phase shift, but others like Pole Position II and Joust look better with a lower (25.7) one.

 

Here is a look at Choplifter! - (25.7 --> 26.7 --> 27.7):

Notice how much better the sky and ground appear with a system that phase shifts higher.

 

Here is a look at Joust - (25.7 --> 26.7 --> 27.7):

Notice how bad the enemy bird wings look with a higher phase shift. They lose their green.

 

Just to emphasize, the above are not utilizing any tint/hue control or manipulation. There is no manual changing of RGB values or proportions. This is not the same as a television display tint/hue control. This comes strictly from the console itself and is not a pot adjustment either.

 

*Note to 7800 game developers: Avoid color E$ like the plague!*

 

Interestingly enough, a 'perfect Fuji' (Enable the BIOS) demands '257-PROSYSTEM' - and it is the technically accurate ideal, if not actually experienced for a long duration of time.

 

Here is the Fuji captured under NTSC (25.7 degrees --> 26.7 degrees --> 27.7 degrees):

*The differences are likely less noticeable on a CRT especially when animated, but still worth noting*

 

If you have a system that truly sticks to a 25.7 degree shift, it's covered here, as well as those going beyond, 26.7 degrees, up to 27.7 degrees.

 

UPDATE 8/28: Received request for less saturated palettes. Lighter/less saturated palettes have been added.

 

Here are the '2X7-PROSYSTEM-LT' palettes (25.7 degrees --> 26.7 degrees --> 27.7 degrees)...

NTSC:

 

 

PAL:

[Trebor]

*UPDATE 8/30 - Download it HERE.

 

It fixes the '257' (25.7 degrees) palettes for both NTSC and PAL regions; data was badly transposed in several areas.

Screen captures updated in first post and documentation cleaned up.

[Trebor]

Theory and speculation at this time... Early models [AT/A1 (some?)] perhaps stick(ed) closer/exact to the 25.7 degrees spec than later models [A1 (most?)/A3/X].

Perhaps as they cheapened on the design so did the quality control over color (phase shifting) due to the components being used and/or other factors.

Looking at titles that appear 'better' at the spec phase shift they tend to be the earlier released arcade titles in the consoles life span (I.E. Joust, Pole Position II).

Games that look 'better' with a higher phase shift (I.E. Commando, Ikari Warriors, Midnight Mutants) tend to be the later titles. Possibly the games were viewed on the respective consoles around their respective release dates and choices were made from what was seen at that time.

Here's Commando, Ikari Warriors and Midnight Mutants. 25.7 degrees on left, 27.7 degrees on right:


Commando...

Flesh tones - From a greenish color to a golden tan.


Ikari Warriors...

The soil/ground.


Midnight Mutants...

Water is surrounding that heart; more purple at 25.7, but blue at 27.7.


Thinking about this some more though, it would probably be better to trace back the motherboard serials rather than the entire console, as even I own a later A1 model with an Expansion Interface (The vast majority of later A1 model do not have one).

Regardless, likely we will never be able to come to a definitive conclusion due to several factors including available data pool - Which would require much interest by the owners of the console (which is a relatively small pool as it is), as well as aging of components skewing data.

Anyhow, just thought I throw my thoughts out there on the matter.

[ColecoGemini]

I wonder if this is not so much a design flaw, but a fully intented result. In lots of cases, the final colors after the shifting occurs are more natural and desirable, especially with some of the arcade ports where the cold startup colors seem to be way off.

Edited August 30, 2013 by ColecoGemini

[Trebor]

I wonder if this is not so much a design flaw, but a fully intented result. In lots of cases, the final colors after the shifting occurs are more natural and desirable, especially with some of the arcade ports where the cold startup colors seem to be way off.

In the later released games, I would say the colors look likely how the programmers 'intended' with the higher phase shift ("natural and desirable" are very subjective though without the actual programmers' input). However, in others (such as Joust demonstrated above), the colors at 25.7 are the closest to Arcade accurate and again likely how the programmer(s) 'intended' it to display. Galaga too is another title - which mimics the Arcade better at the 25.7 mark and steers further away with a higher shift (Again, titles which were programmed and released early).

 

The 25.7 degreee setting too is not a "cold startup" palette. At 'cold' the phase shift is actually much lower. You'll notice this on Choplifter, where the title screen is more of a blue instead of a green (Lower phase shift, colors shift downward).

 

The phase shift is closer to ~24 degrees at 'cold startup'. 25.7 is anywhere from ~90 seconds to 5 minutes of playing on the console from the systems I have seen and tested. I captured one of my systems a few months back which showed it reaching what looks to be the 25.7 tech spec at around the 2 minute mark.

 

Also on two other 7800 systems I own, it does not go any higher than what appears between a 25.7 and 26.7 degrees shift - even after running for several hours.

 

All of this too shows the notion of using the 26.7 degree shift palette to be the most balanced of approaches as all mentioned games do well with that setting.

 

 

Here's Joust, Commando, and Ikari Warriors all looking well under 26.7. Joust looks better at 25.7, and Ikari Warriors and Commando look better at 27.7; but again a happy medium for all is 26.7...

 

 

What would have been ideal is for the programmers who intended to use a more brown color, stuck with F$ and if a green was intended than a D$ (or C$ if a bright-cool green is needed), instead of a E$.

 

For Midnight Mutants, they just needed to use a blue selection one row down, and no purple would have been present for the water at any of the mentioned phase shifts.

 

I'm still leaning towards the timeframe of when the consoles were manufactured (Early or later in the console's lifespan) provided the different colors which influenced the programmers to make the choices they did.

 

I'm pretty confident that if the programmers viewed the 25.7 color palette, they would not have made the choices they did for games like Commando and Ikari Warriors, and if the programmers viewed the palette at 27.7, they would not have made the choices for Joust and Galaga. It's probable the colors selected ('desired') were the ones they saw under the 7800's manufactured at the time of when the game was being developed/finalized.

 

As time passed, they manufactured cheaper designed consoles (I.E. removing the Expansion Interface) and it makes sense the quality control of something that was evidently overlooked - especially considering it is not 'hard-coded', the color palette, slipped through the cracks. In all fairness, just like they didn't have the time to max the system's potential in games programmed for it; something like the color palette would not even be a blip on the radar.