slug: 3d-printing-101-part-8-troubleshooting-optimization-when-pri status: draft title: "3D Printing 101, Part 8: Troubleshooting & Optimization. When Prints Go Wrong (And How to Fix Them)" description: >- Master 3D print troubleshooting for FDM and resin. Diagnose failures visually, fix common issues, and optimize settings for speed and quality. category: tech categoryLabel: Technology date: '2026-06-10' dateFormatted: 'Jun 10, 2026' readTime: 17 min read image: >- https://images.unsplash.com/photo-1509042239860-f550ce710b93?w=400&h=250&fit=crop imageAlt: "Image for 3D Printing 101, Part 8: Troubleshooting & Optimization. When Prints Go Wrong (And How to Fix Them)" featured: false excerpt: >- Even the best printers throw tantrums. Part 8 of our 3D Printing 101 series gives you the diagnostic tools and fixes to conquer every failed print. FDM or resin. shareHook: >- Your print failed AGAIN? 😤 Part 8 of 3D Printing 101 is your complete troubleshooting bible for FDM and resin. Stop guessing, start fixing. 🔧🖨️ heroGradient: from-green-900 via-emerald-800 to-navy-900 accentColor: emerald series_name: "3D Printing 101" series_part: 8 total_parts: 13
Part 7 walked you through materials and filament selection, which means you now have a printer, a slicer, a material strategy, and a head full of optimism. Then you hit print. And something goes wrong.
Maybe the first layer doesn't stick. Maybe the print looks like a melted candle. Maybe you come back an hour later to find a pile of spaghetti on the build plate and a model that gave up somewhere around layer 47. This happens to everyone. It happened to experienced makers this morning. It will happen again tomorrow.
Troubleshooting is the part of 3D printing that nobody puts on the box. It's also the part that separates people who eventually produce reliable, high-quality prints from people who sell their printer after three months. The difference isn't talent. It's method.
This is Part 8 of 13 in the 3D Printing 101 series, and it's the one that makes everything before it click.
Why Prints Fail (And Why That's Actually Normal)
You've learned a lot to get here. Parts 1 through 7 covered how FDM and resin printing work mechanically, how to choose and set up a printer, how slicers translate geometry into motion, how supports work, how to think about materials, and how to finish and post-process your prints. That foundation matters now, because troubleshooting without context is just guessing.
Failure isn't a detour from the learning process. It is the learning process.
The Learning Curve Is Real. And Steep
No one gets a perfect print every time. The variables at play in a single FDM print include nozzle temperature, bed temperature, ambient humidity, filament moisture content, print speed, layer height, cooling fan behavior, and bed adhesion surface condition. That's before you even get into geometry-specific considerations like overhangs and supports. Resin printing adds UV intensity calibration, FEP film condition, and resin chemistry to that list.
The point isn't to eliminate failure. The point is to stop being surprised by it and start being systematic about it. Troubleshooting is a skill you build deliberately, the same way you'd build any other technical skill: by paying attention, keeping records, and isolating variables.
Even makers with years of experience and thousands of hours of print time encounter new failure modes when they switch materials, change environments, or push a design to its limits. Failure is the feedback loop. Learning to read it quickly is what makes someone good at this.
FDM vs. Resin: Different Beasts, Different Failures
FDM and resin printing share almost nothing mechanically, which means they fail for entirely different reasons. FDM failures are usually thermal or mechanical: temperature too high, retraction too aggressive, bed adhesion lost, filament moisture causing steam bubbles mid-extrusion. The problems are physical and often visible in real time.
Resin failures tend to be chemical and optical. The UV light either cures too much or too little. The FEP film creates suction forces that tear layers apart. Supports fail silently until the whole model drops into the vat. By the time you notice a resin failure, it's usually complete.
Understanding which category your failure belongs to tells you immediately where to look. That's not a small thing.
The Troubleshooter's Mindset: Diagnose Before You Tweak
The single most common mistake in 3D printing troubleshooting is changing three settings at once, running another print, and having no idea which change actually helped. It feels productive. It isn't. You've just muddied the data.
"A good scientist changes one variable at a time. A good maker does the same thing. The printer doesn't care about your intuition. It responds to physics."
The scientific method applies here with no modification required. Observe the failure. Form a hypothesis about the cause. Change one thing. Test. Repeat.
One Variable at a Time. The Golden Rule
This is non-negotiable. If your print is stringing, don't simultaneously raise retraction distance, lower temperature, and increase travel speed. Pick the most likely cause based on what you're seeing, change that one setting, and run a test print. A short test print, not the full three-hour model. Most failure modes can be diagnosed with a 15-minute calibration print if you design your test correctly.
Test Prints Save Time
Keep a small library of test prints specifically for calibration: a temperature tower, a retraction test, a bed adhesion test square, and a bridging test. Running a targeted 20-minute test costs far less than rerunning a two-hour model six times chasing a ghost.
Changing one variable at a time also means you build genuine knowledge. After a few months of systematic testing, you'll know exactly how your specific printer responds to humidity changes in your workshop. That knowledge doesn't transfer from a forum post. You build it yourself.
Building Your Print Log Habit
A print log is the highest-leverage habit you can build as a maker. It doesn't need to be elaborate. A note in your phone works. A spreadsheet works better. What matters is consistency.
Document the following for every print: filament brand and material, nozzle temperature, bed temperature, print speed, layer height, ambient room temperature, any humidity readings if you have them, and a brief description of the outcome. Note what failed and where in the print it failed. Note what you changed and why.
Free tools like Obico (formerly The Spaghetti Detective) and OrcaSlicer's built-in print history can automate parts of this. But even a plain text file beats nothing. Within a few months, your log becomes a personal reference that no YouTube video can replicate, because it's calibrated to your exact printer, your exact filament brands, and your exact environment.
FDM Failure Gallery: Identifying Problems by What You See
Diagnosis starts with your eyes. Before you touch a single setting, look at the print. The failure mode is usually visible, and visible failures have known causes. This section is a field guide.
Stringing and Oozing
Stringing looks like a spider web between parts of your print. Thin filament threads connect surfaces that should have nothing between them. It happens during travel moves, when the nozzle crosses open air and leaks molten filament as it goes.
The primary causes are temperature too high (the filament stays liquid and flows freely), retraction distance or speed too low (the filament isn't pulled back far enough before travel), and travel speed too slow (the nozzle spends too long crossing open space). On the FlashForge Inventor, retraction settings are accessible in FlashPrint under filament profile settings. PLA typically performs well with retraction distances between 4mm and 6mm and retraction speeds around 40mm/s to 50mm/s, but your specific filament brand matters.
The fix: print a retraction test tower and a temperature tower before blaming anything else.
Layer Adhesion and Delamination
Layer delamination shows up as visible gaps or cracks between layers, usually horizontal. The layers printed but didn't bond. In severe cases, you can peel layers apart with your fingers.
Causes include print temperature too low for the material (the filament isn't hot enough to fuse with the layer below), print speed too high (the nozzle moves on before adhesion can form), and moisture in the filament (steam bubbles interrupt the extrusion stream). PETG is particularly sensitive to speed; running it too fast produces delamination even at correct temperatures.
If you hear popping or crackling during a print, stop immediately. That's moisture vaporizing inside the hotend. Dry your filament before continuing.
Warping and Bed Adhesion Failures
Warping is when the corners of your print lift off the bed during printing. It's most common with ABS and ASA, which shrink significantly as they cool. The contraction creates internal stress that pulls corners upward.
Fixes include a heated bed (ABS typically needs 100°C to 110°C), an enclosure to maintain ambient temperature, better bed surface preparation (PEI sheets, glue stick, or hairspray depending on material), and brim or raft settings in your slicer to increase the adhesion footprint. The FlashForge Inventor's enclosed build chamber gives it a meaningful advantage with warp-prone materials compared to open-frame printers.
Under-Extrusion and Clogged Nozzles
Under-extrusion looks like thin, weak, or missing sections of wall. Lines that should be solid look gappy or translucent. In severe cases, entire layers are barely there.
Causes: partial clog in the nozzle, extruder tension too loose, temperature too low for the material, or print speed too high for the hotend to keep up. A cold pull (heating the nozzle, loading filament, cooling to around 90°C, then pulling firmly) clears many partial clogs without disassembly. If cold pulls don't work, the nozzle needs replacement.
Spaghetti Prints and Total Collapses
Spaghetti is exactly what it sounds like: a pile of tangled filament where your model used to be. The print detached from the bed or lost a critical support, and the nozzle kept printing into open air, depositing filament with nowhere to go.
This is usually a bed adhesion failure that wasn't caught early, a layer shift that knocked the print loose, or a support structure that failed under the weight of the geometry above it. Prevention is better than cure: check your first layer carefully before walking away, and make sure your supports are dense enough for the geometry they're carrying.
FDM Failure Quick Reference
| Failure | Most Likely Cause | First Fix to Try |
|---|---|---|
| Stringing | Temp too high or retraction too low | Print a retraction test tower |
| Delamination | Temp too low or speed too high | Increase print temp by 5°C increments |
| Warping | Adhesion or cooling | Add brim; raise bed temp |
| Under-extrusion | Partial clog or tension | Cold pull; check extruder tension |
| Spaghetti | Bed adhesion failure | Check first layer; add brim or raft |
FDM Fixes: Dialing In Your FlashForge Inventor
Identifying a failure is half the job. The other half is knowing exactly what to change and by how much. Vague adjustments produce vague results.
Temperature Tuning: Finding the Sweet Spot
Every filament brand has a rated temperature range, and every printer runs slightly differently. The temperature your slicer sends to the hotend is not necessarily the temperature at the nozzle tip. Thermal variation between printers of the same model can be several degrees in either direction.
A temperature tower is the standard solution. It's a single print that changes temperature at defined intervals, usually every 5°C or 10°C, so you can compare how the same filament behaves across a range. Print one for every new filament brand you introduce. The results are specific to your printer and your filament, which is exactly the kind of data you need.
For the FlashForge Inventor, general starting points are: PLA at 200°C to 210°C nozzle, 60°C bed; PETG at 230°C to 240°C nozzle, 70°C to 80°C bed; ABS at 230°C to 240°C nozzle, 100°C to 110°C bed with enclosure. These are starting points, not final answers. Your specific filament brand may prefer something different.
Retraction Settings That Actually Work
Retraction is the brief backward pull of filament that happens before a travel move, intended to prevent oozing. Too little retraction and you get stringing. Too much and you get clogs or grinding.
The FlashForge Inventor uses a Bowden-style extruder on some configurations and direct drive on others depending on the model variant. Bowden setups generally need more retraction (4mm to 7mm) because the filament path is longer. Direct drive setups typically need less (1mm to 3mm). Retraction speed matters too: too fast and the filament can snap or grind; too slow and it doesn't pull back in time. Start at 40mm/s and adjust based on test results.
In FlashPrint, retraction settings live under the filament profile editor. Make changes there rather than in the per-print settings so your calibration carries forward.
Bed Leveling and First Layer Perfection
The first layer is everything. A bad first layer means a failed print. There's no recovering from it partway through.
The First Layer Rule
If your first layer doesn't look right, stop the print. Don't hope it improves. It won't. Re-level the bed, adjust your Z offset, and start again. Five minutes now saves two hours of wasted filament later.
The FlashForge Inventor includes assisted bed leveling that walks you through a multi-point leveling sequence. Run it every 10 to 15 prints, or any time you change filament types or move the printer. After leveling, fine-tune your Z offset (the distance between the nozzle and the bed at the start of the print) until the first layer squishes slightly into the surface without being so compressed that it drags.
A good first layer looks slightly wider than the filament diameter and adheres completely without gaps. A bad first layer either floats above the bed (Z offset too high) or grinds into it (Z offset too low).
Dealing with Moisture-Damaged Filament
Filament absorbs moisture from the air. PLA is relatively tolerant. PETG and Nylon are not. Moisture-damaged filament produces popping sounds during printing, rough or bubbly surface texture, weak layer adhesion, and inconsistent extrusion.
The fix is drying. A food dehydrator set to 45°C to 50°C for PLA or 55°C to 65°C for PETG for four to six hours restores most moisture-damaged filament. A dedicated filament dryer like the Sunlu S2 works well and holds spools upright during drying. Store filament in sealed containers with desiccant between uses. In humid climates or humid seasons, this isn't optional.
Resin Failure Gallery: What Went Wrong in the Vat
Resin failures are a different category of frustration. FDM failures are usually visible in progress. Resin failures often aren't discovered until you open the cover, lift the build plate, and find either nothing attached to it or a cured mass stuck to the FEP film at the bottom of the vat. By then, the damage is done.
The physics of resin printing create failure modes that don't exist in FDM at all. Understanding them changes how you approach every print.
Print Didn't Stick to the Build Plate
This is the most common resin failure. You run a print, lift the build plate, and find nothing. The model either stayed in the vat (stuck to the FEP) or fell apart during printing.
Causes include bottom exposure time too short (the first layers didn't cure long enough to bond to the build plate), Z offset too high (the nozzle isn't close enough
Resin Fixes: Dialing In Your Anycubic Photon S
The Photon S is a capable machine. It's also unforgiving when your settings are even slightly off. Resin printing rewards precision in a way FDM doesn't quite demand, and the good news is that precision is learnable. These four areas cover the majority of failures you'll encounter.
Exposure Calibration: The RERF Test Explained
The RERF (Resin Exposure Range Finder) is the single most useful calibration print you can run on the Photon S. It prints a matrix of small test tiles, each exposed at a different time increment, so you can visually identify the sweet spot for your specific resin and ambient conditions before committing to a full print.
Here's how to run it:
- Download the RERF file from Anycubic's official resources or generate one in Photon Workshop.
- Pour fresh, well-shaken resin into the vat. Don't reuse resin that's been sitting uncovered.
- Set your base exposure time to 40 seconds and your normal layer exposure to the resin manufacturer's starting recommendation (typically 6–9 seconds for Anycubic standard resin).
- Print the RERF without supports. It adheres directly to the build plate.
- After washing and curing, examine each tile. You're looking for the one with the sharpest text, cleanest edges, and no bleeding or under-cure artifacts.
- Note the exposure time that produced that tile. That's your new baseline.
For Anycubic standard resin, a starting exposure of 6–8 seconds per layer at 0.05mm is typical. For ABS-like resin, start at 8–10 seconds. These are starting points. The RERF tells you the truth.
In Photon Workshop, navigate to Print Settings and adjust the Normal Exposure Time and Bottom Exposure Time separately. Bottom layers need significantly more exposure to bond to the build plate, typically 40–60 seconds for 6–8 bottom layers.
Z Offset and Build Plate Leveling
The Z offset controls how close the build plate sits to the FEP film at the very start of a print. Too far away and your first layers won't bond. Too close and you'll crush resin into the FEP, potentially damaging it or locking the plate in place.
On the Photon S, leveling the build plate is a physical process:
- Home the Z axis using the touchscreen.
- Loosen the build plate locking screw slightly.
- Place a sheet of regular printer paper on the FEP film.
- Lower the build plate manually until it rests on the paper with light resistance when you pull.
- Tighten the locking screw firmly while maintaining that position.
- Set Z=0 in the menu.
After leveling, adjust Z offset in small increments. A change of just 0.1mm is enough to fix adhesion failures or over-squish. Small changes have outsized impact here.
Support Strategy for Reliable Prints
Supports in resin printing aren't just scaffolding. They're the difference between a print that survives and one that detaches mid-job and becomes a cured blob at the bottom of your vat.
For standard prints (miniatures, functional parts, display pieces), use medium supports with a tip diameter of 0.4–0.6mm and a density of 40–60%. For highly detailed prints (jewelry, fine facial features, text), drop to light supports with 0.3mm tips and increase density to 65–75% to prevent fine features from sagging before they cure.
Always orient your model to minimize large flat surfaces facing the build plate. Large flat surfaces create enormous peel forces that supports can't always survive.
FEP Film Inspection and Replacement
The FEP film is the transparent layer at the bottom of your resin vat. It takes punishment every single print as layers peel away from it. Inspect it before every session.
Hold the vat up to a light source and look for:
- Cloudiness or milky patches: The film is delaminating. Replace it soon.
- Visible scratches: Minor surface scratches are normal. Deep scratches scatter UV light and ruin fine detail.
- Micro-tears or pinholes: Print-ending failures waiting to happen. Replace immediately.
Safety First: FEP Replacement
Resin is a skin and eye irritant. Wear nitrile gloves and eye protection when handling the vat or replacing FEP. Work in a ventilated space. Dispose of resin-contaminated materials according to your local regulations, never pour liquid resin down the drain.
To replace the FEP, remove the vat frame screws, peel out the old film, cut new FEP film to size, and tension it evenly across the frame before re-securing the screws. Uneven tension causes print failures just as surely as a damaged film does. Tighten screws in a star pattern, not sequentially around the edge.
Optimization: Printing Faster Without Sacrificing Quality
Optimization isn't a race. It's a negotiation. You're trading something, time, surface quality, material, or structural integrity, and the goal is to make that trade consciously rather than accidentally.
Speed vs. Quality: Understanding the Trade-Off
Every setting in your slicer exists on a spectrum. Faster isn't always worse, and slower isn't always better. The printers covered in this series, the FlashForge Inventor for FDM and the Anycubic Photon S for resin, both have meaningful optimization headroom once you understand what you're actually adjusting.
The mistake most people make is treating speed as the variable and everything else as fixed. Flip that. Decide what quality level the print actually needs, then find the fastest settings that deliver it.
Strategic Layer Height Selection
Layer height is the single most powerful variable in FDM optimization. Halving your layer height roughly doubles your print time. Doubling it cuts time nearly in half.
For the FlashForge Inventor with a standard 0.4mm nozzle:
- 0.1mm: Maximum detail. Use for display pieces, visible surfaces, cosplay props.
- 0.2mm: The reliable all-rounder. Good detail, reasonable time.
- 0.3mm: Fast. Acceptable for structural parts, prototypes, anything that won't be seen closely.
Adaptive layers (called variable layer height in most slicers) automatically use finer layers on curved surfaces and coarser layers on flat vertical sections. Enable it for any print that combines organic curves with flat walls. The time savings are real without visible quality loss on the parts that matter.
Infill Optimization for Strength and Speed
Infill percentage gets misunderstood. Most prints don't need more than 15–20%. Walls carry most structural load. Infill primarily prevents surface collapse and adds mass.
Infill Pattern Guide
Grid: Fast to print, adequate for most non-directional loads. Good default choice. Gyroid: Slightly slower but isotropic, meaning it handles stress from any direction equally. Use it for parts that flex, twist, or take impacts. It also uses less material than grid at equivalent strength. Concentric: Best for flexible parts. Terrible for rigid structural prints.
For walls versus infill, increasing wall count from 2 to 4 does more for part strength than increasing infill from 20% to 50%. More perimeters, not more fill.
Anti-Aliasing and Exposure Tuning for Resin Detail
Resin printers work in pixels. Every layer is a projected image, and pixel edges create visible stepping on curved surfaces. Anti-aliasing in Photon Workshop blurs those pixel boundaries by exposing edge pixels at partial intensity, softening the transition between cured and uncured resin.
Enable anti-aliasing in Photon Workshop under the display settings. Set grey level to 4 or 8. Higher values produce smoother curves but require slight exposure compensation, typically adding 0.5–1 second to normal layer exposure to maintain full cure depth.
Lift speed and bottom lift speed are often left at defaults and then blamed for other problems. Slow lift speed (1–2 mm/s) reduces peel stress on supports and delicate features. Bottom lift speed should always stay at or below 1 mm/s for the first 6–8 layers. Rushing this phase is a reliable way to rip prints off the plate.
Environmental Factors: The Hidden Culprits
Your printer doesn't exist in a vacuum. The room it sits in, the season, the humidity, the window across the room, all of it affects your prints in ways that no slicer setting can compensate for.
Temperature and Humidity Effects on FDM
Cold ambient temperatures cause filament to cool too quickly after extrusion, increasing warping and reducing layer adhesion. PLA starts struggling below 18°C in an unenclosed printer. ABS needs a fully enclosed environment and ambient temps above 25°C to print reliably without warping.
Humidity is slower and sneakier. Filament absorbs moisture from the air over days and weeks, and wet filament pops, bubbles, and strings in ways that look like temperature or retraction problems. If your prints suddenly get worse without any setting changes, check when you last opened that spool.
Store filament in sealed containers with fresh desiccant. A simple vacuum bag with a hygrometer works. A purpose-built dry box with active heating works better. Part 2 of this series covered workspace setup; those principles apply here especially when it comes to keeping your filament away from exterior walls where temperature swings are worst.
Ambient Light and Temperature for Resin Printing
Resin is photosensitive. That's the whole point. But it means any UV source in your workspace, including sunlight through a window, can begin curing resin in the vat before you've even started a print.
Work in a space without direct sunlight exposure. If your workspace has windows, print with the blinds closed or position the printer away from the light path. Standard indoor LED lighting is generally fine, but UV-emitting bulbs or natural light are real problems.
Warm rooms shorten resin pot life and reduce viscosity. Below 20°C, resin thickens and prints poorly. Above 30°C, it becomes too fluid and may cure inconsistently. The ideal resin printing temperature is 20–25°C. In winter, warm the resin bottle in a warm water bath for 10 minutes before pouring.
Quick-Reference Troubleshooting Tables
These tables are built for the moment things go wrong mid-session. Bookmark this section. You'll use it.
How to Use These Tables
Severity ratings: Minor means the print may still finish usably. Major means quality is significantly compromised. Fatal means the print is likely lost. Cross-references point to earlier sections in this article for deeper explanation.
FDM: Symptom → Cause → Fix
| Symptom | Likely Cause | Fix | Severity |
|---|---|---|---|
| Warping / corners lifting | Bed temp too low; cold room | Increase bed temp; add brim; enclose printer | Major |
| Layer separation / delamination | Print temp too low; speed too high | Raise nozzle temp 5°C; reduce speed | Major |
| Stringing between features | Retraction too low; temp too high | Increase retraction distance; lower temp 5°C | Minor |
| Under-extrusion (gaps in layers) | Partial clog; wet filament; too fast | Cold pull; dry filament; reduce speed | Major |
| Over-extrusion (blobby surface) | Flow rate too high | Reduce flow rate to 95% and calibrate | Minor |
| First layer not sticking | Bed not level; Z offset wrong; dirty bed | Relevel bed; clean with IPA; adjust Z offset | Fatal |
| Elephant foot (flared base) | Bed temp too high; Z offset too low | Lower bed temp; raise Z offset slightly | Minor |
| Ghosting / ringing artifacts | Print speed too high; loose belts | Reduce speed; check belt tension | Minor |
| Clogged nozzle | Burnt filament; wrong temp; debris | Cold pull or needle clear; check temp | Major |
| Inconsistent extrusion | Worn extruder gear; bowden slip | Inspect extruder; re-seat bowden tube | Major |
| Pillowing on top surface | Too few top layers; cooling too slow | Add 1–2 top layers; increase fan speed | Minor |
Resin: Symptom → Cause → Fix
| Symptom | Likely Cause | Fix | Severity |
|---|---|---|---|
| Print doesn't stick to build plate | Z offset too high; under-exposed base | Relevel plate; increase bottom exposure | Fatal |
| Print sticks to FEP instead of plate | Z offset too low; over-exposed base | Raise Z offset; reduce bottom exposure | Fatal |
| Layer separation mid-print | Exposure too low; lift speed too high | Increase exposure; slow lift speed | Fatal |
| Supports failing | Tip size too small; density too low | Use medium supports; increase density | Major |
| Cloudy or milky surface finish | FEP film degraded; resin contamination | Inspect and replace FEP; strain resin | Major |
| Elephant foot (flared base layers) | Bottom exposure too high | Reduce bottom exposure by 5–10 seconds | Minor |
| Suction cupping (hollow parts) | No drain holes; lift speed too slow | Add drain holes in model; adjust lift speed | Major |
| Fine detail missing or soft | Under-exposed; anti-aliasing off | Increase exposure; enable anti-aliasing | Minor |
| Resin not curing fully | Old or contaminated resin; FEP cloudy | Replace resin; replace FEP | Major |
| Print warping after removal | Insufficient post-cure; uneven cure | Extend post-cure time; cure from all sides | Minor |
| Bubbles in print surface | Resin not mixed; air in vat | Shake resin thoroughly before pouring | Minor |
These tables cover the issues that appear most often in this series. As you move into post-processing in Part 9, you'll encounter a few finish-related problems that have their own diagnostic logic, and those get their own reference material there.
Your Troubleshooting Action Plan: Put It Into Practice
You now have a framework. Observation, isolation, adjustment, verification. That's the loop. Every problem in this article, every warped corner, every failed resin layer, every stringy mess, follows the same diagnostic path. You observe the symptom, isolate the most likely cause, make one change, and verify the result.
Reading about it is useful. Practicing it is what actually builds the skill.
This Week's Diagnostic Challenge
Before moving to Part 9, complete these actions. They're not optional homework. They're the difference between knowing this material and owning it.
Part 9 covers post-processing, sanding, priming, painting, and finishing the prints you've now learned to fix. Everything in that lesson assumes you have prints that actually came out right
